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Markus Peter Hehlen

Markus Hehlen

Email
Phone (505) 665-1737

Capabilities

  • Chemical Science
  • Physical chemistry
  • Remote optical spectroscopic measurements
  • Materials chemistry
  • Computational Physics and Applied Mathematics
  • Numerical modeling
  • Monte Carlo methods
  • Earth and Space Sciences
  • Gamma ray detection
  • Sensor technology
  • High Energy Density Plasmas and Fluids
  • Neutron imaging
  • Materials
  • Functional materials
  • Radiological materials
  • Metals casting
  • Novel manufacturing methods
  • Microfabrication
  • Radiation detectors
  • Materials synthesis (single crystals)
  • Superconductivity
  • Optics and fiber optics
  • Ultrafast optical spectroscopies
  • Photoemission spectroscopies
  • Condensed matter
  • Organic/inorganic crystalline and amorphous composites
  • Nuclear and Particle Physics, Astrophysics, and Cosmology
  • Detector expertise in nuclear threat reduction
  • Neutrons
  • Weakly interacting massive particles (WIMP)
  • Hybrid neutron/gamma imaging
  • Science of Signatures - Remote and Standoff Sensing
  • Nuclear radiation sensing and sensors
  • Ground-based sensing and sensors
  • Gamma-rays
  • Neutrons
  • Photon
  • Remote sensing
  • Sensor technology
  • CINT
  • Synthesis
  • Fabrication
  • Structure Measurements
  • Property Measurements
  • SensorNexus: Radiological/Nuclear
  • New Neutron Detector Materials

Expertise

Synthesis and characterization of advanced rare-earth-doped optical materials

Scintillators, laser materials, solid-state optical refrigeration, radiation-balanced lasers

Engineering of photonic devices

Single crystal growth and glass fabrication

Optical raytracing simulations and thin-film coating design

Heat transport, cryogenics, and active thermal management

Technology transfer and commercialization

Education

Postdoctoral Fellow, University of Michigan, Ann Arbor, MI (1996-1998)

Postdoctoral Research Associate, LANL (1994-1996)

Ph.D. in Inorganic and Physical Chemistry, University of Bern, Switzerland (1994)

M.S. in Chemistry, University of Bern, Switzerland (1990)

B.S. in Economics, College of Economics, Bern, Switzerland (1985)

 

LANL Positions

Scientist 4, Materials Science & Technology Division (MST-7) (2010-present)

Scientist 3, Chemistry Division (C-CDE) (2006-2010)

Technical Staff Member, Lujan Neutron Scattering Center (LANSCE-LC) (2003-2006)

Postdoctoral Research Associate, Chemistry Division (1994-1996)

 

Professional Societies

Senior Member of the Optical Society of America (OSA)

 

Awards

LANL Distinguished Performance Award for contributions to the National Explosives Engineering Security Sciences (NEXESS) project on homemade explosives (2013)

LANL Pollution Prevention Silver Award, Category Change Agents (2013)

Los Alamos National Laboratory Award (LAAP) for exemplary performance in Research & Development (2011)

 

Patents

U.S. Patent: C. Dye, M.P. Hehlen, “Multicolor light emitting diode treatment system with uniform illumination”, #20160175609, issued (2017)

U.S. Patent: D.V. Seletsky, R.I. Epstein, M.P. Hehlen, M. Sheik-Bahae, “Solid-state optical refrigeration using Stark manifold resonances in crystals”, issued (2017)

U.S. Patent 7,263,247: M.P. Hehlen, W.K. Bischel, “Integrated optical isolator array”.

U.S. Patent 7,235,150 and international patents (WO/2000/065600): W.K. Bischel, D.K. Wagner, H. Guenther, S.J. Field, M.P. Hehlen, R.B. Tompane, A.T. Ryan, G.C. Fanning, J.W. Li, N.D. Morozova, “Multi-channel laser pump source for optical amplifiers”.

U.S. Patent 6,580,842: M.P. Hehlen, W.K. Bischel, “Integrated optical circulator array”.

U.S. Patent 6,560,387: M.P. Hehlen, W.K. Bischel, “Doped fiber amplifier utilizing integrated circulator array”.

U.S. Patent 6,208,791 and international patents (WO/2000/063614): W.K. Bischel, D.A. Deacon, N.J. Cockroft, M.P. Hehlen, D.K. Wagner, R.B. Tompane, S.J. Field, “Optically integrating pixel microstructure”

An additional 6 patent applications are currently pending.

 

 

Publications

Also see: https://scholar.google.com/citations?user=FsBVckgAAAAJ&hl=en&oi=ao

Review Articles, Book Chapters, and Books:

  1. M.P. Hehlen, N.A. Smith, M.W. Blair, A. Li, S. Stange, R.D. Gilbertson, E.A. McKigney, R.E. Muenchausen, “Nanocomposite Scintillators”, in Nanocomposite, ceramic, and thin-film scintillators, M. Nikl (ed.), Pan Stanford Publishing Pte Ltd, Singapore, (2017).
  2. M.P. Hehlen, M.L.F. Phillips, N.J. Cockroft, H.U. Güdel, “Upconversion Phosphors”, in Reference Module in Materials Science and Materials Engineering, Elsevier Science Ltd. (2016). http://dx.doi.org/10.1016/B978-0-12-803581-8.02419-X
  3. M.P. Hehlen, M. Sheik-Bahae, R.I. Epstein, “Solid-state optical refrigeration”, in The Handbook on the Physics and Chemistry of Rare Earths, Vol. 45 (2014) 179-260.
  4. “Focus issue introduction: Advanced Solid-State Lasers (ASSL) 2013”, Eds. Y. Jeong, S. Jiang, K. Gallo, T. Südmeyer, M.P. Hehlen, T. Taira, Opt. Express 22 (2014) 8813-8820.
  5. M.P. Hehlen, M. Sheik-Bahae, R.I. Epstein, S.D. Melgaard, D.V. Seletskiy, “Materials for optical cryocoolers”, J. Mat. Chem. C, 1 (2013) 7471-7478. http://dx.doi.org/10.1039/c3tc31681e
  6. M.P. Hehlen, M.G. Brik, K.W. Krämer, “50th anniversary of the Judd-Ofelt theory: An experimentalist’s view of the formalism and its application”, J. Lumin. 136 (2013) 221-239. http://dx.doi.org/10.1016/j.jlumin.2012.10.035.  
  7. “Focus issue introduction: Persistent phosphors”, Eds. P.F. Smet, D. Poelman, and M.P. Hehlen, Opt. Mater. Expr. 2 (2012) 452-454. http://dx.doi.org/10.1364/OME.2.000452.
  8. D.V. Seletskiy, M.P. Hehlen, R.I. Epstein, M. Sheik-Bahae, “Cryogenic optical refrigeration”, Adv. Opt. Photon., 4 (2012) 78-107. http://dx.doi.org/10.1364/AOP.4.000078.
  9. M.P. Hehlen, “Design and fabrication of rare-earth-doped laser cooling materials”, in Optical Refrigeration. Science and Applications of Laser Cooling of Solids, Eds. R.I. Epstein and M. Sheik-Bahae, Wiley, Weinheim (2009). http://dx.doi.org/10.1002/9783527628049.ch2.
  10. M.P. Hehlen, M.L.F. Phillips, N.J. Cockroft, H.U. Güdel, “Upconversion Phosphors”, in the Encyclopedia of Materials: Science and Technology, Elsevier Science Ltd. (2001), p.9456-9458.
  11. M.P. Hehlen, “Personal Computer (PC) – Der Einstieg”, Verlag Paul Haupt, Bern (1990).

Peer Reviewed Publications:

  1. D.T. Wakeford, S.R. Tornga, J.C. Adams, O.C. Trautshold, M.P. Hehlen, “Improved Scintillation Detector Performance via a Method of Enhanced Layered Coatings”, IEEE Transactions on Nuclear Science, June 2017, accepted for publication.
  2. S.D. Melgaard, A. Albrecht, M.P. Hehlen, M. Sheik-Bahae, “Solid-state optical refrigeration reaches sub-100 Kelvin regime”, Nature Sci. Rep. 6 (2016) 20380. http://dx.doi.org/10.1038/srep20380
  3. W.L. Boncher, T.C. Lin, N.L. Cordes, M.P. Hehlen, “Sequestration of Cerium (III) Bromide in mesoporous silica”, Micropor. Mesopor. Mat., 211 (2015) 158-161.   http://dx.doi.org/10.1016/j.micromeso.2015.03.007
  4. M.P. Hehlen, W.L. Boncher, S.P. Love, “Design study of a laser-cooled infrared sensor”, Proc. SPIE 9380 (2015) 938000I-1. http://dx.doi.org/10.1117/12.2077846
  5. W.L. Boncher, E. Judge, J.-M. Sansinena, M.R. Dirmyer, M.P. Hehlen, “Purification of precursors of Yb3+-doped YLF crystals by solvent extraction and electrochemical processing”, Proc. SPIE 9380 (2015) 938004-1. http://dx.doi.org/10.1117/12.2077235                    
  6. K.D. Ianakiev, M.P. Hehlen, M.T. Swinhoe, A. Favalli, M.L. Iliev, T.C Lin, B.L. Bennett, M.T. Barker, “Neutron detector based on particles of 6Li glass scintillator dispersed in organic light guide matrix”, Nucl. Instr. Meth. Phys. Res. A, 784 (2015) 189-193. http://dx.doi.org/10.1016/j.nima.2014.10.073 .
  7. R.I. Epstein, M.P. Hehlen, M. Sheik-Bahae, S.D. Melgaard, “Optical cryocoolers for sensors and electronics”, Invited, Proc. SPIE 9070 (2014) 90702K. http://dx.doi.org/10.1117/12.2052941.
  8. K.V. Vasudevan, W.L. Boncher, N.A. Smith, M.W. Blair, B.L. Scott, B.L. Bennett, M.P. Hehlen, R.E. Muenchausen, J.C. Gordon, “Nitrile-supported coordination polymers of Cerium (III) Bromide”, Eur. J. Inorg. Chem., 13 (2014) 2213. http://dx.doi.org/10.1002/ejic.201400030
  9. G. Lakshminarayana, J.A.Torres, T.C. Lin, I.V. Kityk, M.P. Hehlen, “Sol-gel synthesis and characterization of fluoride-rich lanthanum-alumino-silicate gels doped with Ce3+ and Ti4+”, J. Alloys Comp. 601 (2014) 67-74. http://dx.doi.org/10.1016/j.jallcom.2014.02.098
  10. M.P. Hehlen, W.L. Boncher, S.D. Melgaard, M.W. Blair, R.A. Jackson, T.E. Littleford, S.P. Love, “Preparation of high-purity LiF, YF3, and YbF3 for laser refrigeration”, Invited, Proc. SPIE 9000 (2014) 900004. http://dx.doi.org/10.1117/12.2039547.
  11. R.I. Epstein, M. Sheik-Bahae, M.P. Hehlen, “Optical refrigerators outshine thermoelectric coolers”, IEEE Phot. Soc. News, 28 (2014) 9-11.
  12. J.R. Silva, L.H.C. Andrade, S.M. Lima, M.P. Hehlen, Y. Guyot, A.N. Medina, L.C. Malacarne, N.G.C. Astrath, M.L. Baesso, “Laser-induced lensing effects in solid-state optical refrigerators”, Appl. Phys. Lett., 102 (2013) 141910 (4 pp.). http://dx.doi.org/10.1063/1.4801838
  13. G. Lakshminarayana, E. M. Weis, A. C. Lira, U. Caldiño, D. J. Williams, M. P Hehlen, “Cross relaxation in rare-earth-doped oxyfluoride glasses”, J. Lumin., 139 (2013) 132-142. http://dx.doi.org/10.1016/j.jlumin.2013.02.039.
  14. J. R. Silva, N. G. C. Astrath, L. C. Malacarne, M. L. Baesso, S. M. Lima, L. H. C. Andrade, C. Jacinto, M. P. Hehlen, “Modeling the population lens effect in thermal lens spectrometry”, Opt. Lett. 38 (2013) 422-424. http://dx.doi.org/10.1364/OL.38.000422.
  15. M.W. Blair, M. Fasoli, S.C. Tornga, A. Vedda, N.A. Smith, B.L. Bennett, M.P. Hehlen, R.E. Muenchausen, “Nanophosphor GdOBr:Ce via combustion synthesis: unique luminescence results”, phys. stat. sol. (c) 10 (2013) 227-231. http://dx.doi.org/10.1002/pssc.201200525.
  16. M.P. Hehlen, R.R. Greco, W.G. Rellergert, S.T. Sullivan, D. DeMille, R.A. Jackson, E.R. Hudson, J.R. Torgerson, “Optical spectroscopy of an atomic nucleus: Progress toward direct observation of the 229Th isomer transition”, J. Lumin. 133 (2013) 91. http://dx.doi.org/10.1016/j.jlumin.2011.09.037.
  17. M.P. Hehlen, A.H. Mueller, N.R. Weisse-Bernstein, R.I. Epstein, “Electrocaloric refrigerator using electrohydrodynamic flows in dielectric fluids”, Invited, Proc. SPIE 8638 (2013) 86380D-1. http://dx.doi.org/10.1117/12.2004009
  18. G. Lakshminarayana, E.M. Weis, B.L. Bennett, A. Labouriau, D.J. Williams, J.G. Duque, M. Sheik-Bahae, M.P. Hehlen, “Structural, thermal, and luminescence properties of oxyfluoride glasses highly doped with cerium fluoride”, Opt. Mater., 35 (2012) 117. http://dx.doi.org/10.1016/j.optmat.2012.07.022.
  19. A. Li, N. Smith, M.P. Hehlen, E.A. McKigney, R. Gardner, “Light yield measurement method for milled nanosize inorganic crystals”, Appl. Rad. Isotopes, 70 (2012) 1219-1222. http://dx.doi.org/10.1016/j.apradiso.2011.09.021.
  20. W.M. Patterson, P.C. Stark, T.M. Yoshida, M. Sheik-Bahae, M.P. Hehlen, “Preparation and characterization of high-purity metal fluorides for photonic applications”, J. Am. Ceram. Soc. 94 (2011) 2896. http://dx.doi.org/10.1111/j.1551-2916.2011.04641.x.
  21. A. Li, R. Gardner, N. Smith, M.P. Hehlen, V. Montoya, J.M. Cook, E.A. McKigney, “Light yield measurements of milled BaFCl:Eu inorganic Crystals”, Proc. SPIE 8144 (2011) 814404.   http://dx.doi.org/10.1117/12.894632.
  22. W.G. Rellergert, D. DeMille, R.R. Greco, M.P. Hehlen, J.R. Torgerson, E.R. Hudson, “Constraining the evolution of the fundamental constants with a solid-state optical frequency reference based on the 229Th nucleus”, Phys. Rev. Lett. 104 (2010) 200802. http://dx.doi.org/10.1103/PhysRevLett.104.200802.
  23. W.M. Patterson, M. Sheik-Bahae, R.I. Epstein, M.P. Hehlen, “Model of laser-induced temperature changes in solid-state optical refrigerators”, J. Appl. Phys. 107 (2010) 063108. http://dx.doi.org/10.1063/1.3277009.
  24. W.M. Patterson, D.V. Seletskiy, M. Sheik-Bahae, R.I. Epstein, M.P. Hehlen, “Measurement of solid-state optical refrigeration by two-band differential luminescence thermometry”, J. Opt. Soc. Am. B, 27 (2010) 611. http://dx.doi.org/10.1364/JOSAB.27.000611.
  25. M.P. Hehlen, B.L. Bennett, A. Castro, D.J. Williams, S.C. Tornga, R.E. Muenchausen, “Synthesis and optical properties of Ga2S3-Na2S-CsCl glasses”, Opt. Mater., 32 (2010) 491. http://dx.doi.org/10.1016/j.optmat.2009.11.001.
  26. M.P. Hehlen, “Crystal-field effects in fluoride crystals for optical refrigeration”, Invited, Proc SPIE, 7614 (2010) http://dx.doi.org/10.1117/12.845626.
  27. M.P. Hehlen, “Novel materials for laser refrigeration”, Proc. SPIE, 7228 (2009) 72280E. http://dx.doi.org/10.1117/12.809091.
  28. W.M. Patterson, M.P. Hehlen, M. Sheik-Bahae, R.I. Epstein, “Synthesis and evaluation of ultra-pure, rare-earth-doped glass for laser refrigeration”, Proc. SPIE, 7228 (2009) 72280C. http://dx.doi.org/10.1117/12.811914.
  29. M.E. Manley, F. Trouw, D. Teter, M.P. Hehlen, P.A. Papin, D.J. Thoma, W.L. Hults, “Phonon-confinement entropy and the formation of CeH2.84 nanoplates by fracture”, Phys. Rev. B 78 (2008) 020101(R). http://dx.doi.org/10.1103/PhysRevB.78.020101.
  30. W. Dmowski, S.B. Vakhrushev, I.-K. Jeong, M.P. Hehlen, F. Trouw, T. Egami, “Local lattice dynamics and the origin of the relaxor ferroelectric behavior”, Phys. Rev. Lett. 100 (2008) 137602.  http://dx.doi.org/10.1103/PhysRevLett.100.137602.
  31. M.P. Hehlen, R.I. Epstein, W.M. Patterson, “Synthesis of ultrapure ZBLAN glass for laser refrigeration”, Proc. SPIE 6907 (2008) 69070A. http://dx.doi.org/10.1117/12.762146.
  32. S. Chang, P. Karen, M.P. Hehlen, F.R. Trouw, R.J. McQueeney, “Damping of antiferromagnetic spin waves by valence fluctuations in the double layer perovskite YBaFe2O5”, Phys. Rev. Lett. 99 (2007) 037202. http://dx.doi.org/10.1103/PhysRevLett.99.037202.
  33. M.P. Hehlen, R.I. Epstein, H. Inoue, “Model of Laser Cooling in Yb3+-Doped Fluorozirconate Glass ZBLAN”, Phys. Rev. B 75 (2007) 144302. http://dx.doi.org/10.1103/PhysRevB.75.144302.
  34. R. J. McQueeney, J. Ma, S. Chang, J.-Q. Yan, M.P. Hehlen, and F. Trouw, “Stabilization of charge ordering in La1/3Sr2/3FeO3-d by magnetic exchange”, Phys. Rev. Lett. 98 (2007) 126402. http://dx.doi.org/10.1103/PhysRevLett.98.126402.
  35. M.P. Hehlen, R.I. Epstein, “Ultrapure ZBLAN Glass for Optical Refrigerators”, Proc. SPIE 6461 (2007) 646103, http://dx.doi.org/10.1117/12.708304.
  36. A.C. Lawson, J.A. Roberts, B. Martinez, M. Ramos, G. Kotliar, F.W. Trouw, M.R. Fitzsimmons, M.P. Hehlen, J.C. Lashley, H. Ledbetter, R.J. McQueeney, A. Migliori, “Invar Model for d-phase Pu: Thermal Expansion, Elastic, and Magnetic properties”, Philos. Mag., 86 (2006) 2713. http://dx.doi.org/10.1080/14786430500155262.
  37. M.P. Hehlen, R.I. Epstein, H. Inoue, “Laser Cooling of Rare-Earth-Doped Solids: The Next Step”, Proc. SPIE, 6130 (2006) 61300N. http://dx.doi.org/10.1117/12.663663 .
  38. A.D. Christianson, J.M. Lawrence, A.M. Lobos, A.A. Aligia, E.D. Bauer, N.O. Moreno, C.H. Booth, E.A. Goremychkin, J.L. Sarrao, J.D. Thompson, C.D. Batista, F.R. Trouw, M.P. Hehlen, “Anisotropic intermediate valence in Yb2M3Ga9 (M=Rh,Ir)”, Phys. Rev. B, 72 (2005) 081102.  http://dx.doi.org/10.1103/PhysRevB.72.081102.
  39. A.D. Christianson, P.S. Riseborough, N.O. Moreno, P.G. Pagliuso, E.D. Bauer, J.L. Sarrao, W. Bao, E.A. Goremychkin, S. Kern, F.R. Trouw, M.P. Hehlen, “Crystal field effects in CeIrIn5”, J. Neutron Res. 13 (2005) 179. http://arxiv.org/pdf/cond-mat/0402020v1.
  40. A.D. Christianson, E.D. Bauer, J.B. Lawrence, P.S. Riseborough, N.O. Moreno, P.G. Pagliuso, J.L. Sarrao, W. Bao, E.A. Goremychkin, F.R. Touw, M.P. Hehlen, R.J. McQueeney, “Crystalline Electric Field Effects in CeMIn5: Superconductivity and the Influence of Kondo Spin Fluctuations”, Phys. Rev. B , 70 (2004) 134505. http://dx.doi.org/10.1103/PhysRevB.70.134505.
  41. K.W. Krämer, D. Biner, G. Frei, H.U. Güdel, M.P. Hehlen, S.R. Lüthi, “Hexagonal sodium yttrium fluoride based green and blue emitting upconversion phosphors”, Chem. Mater. 16 (2004) 1244. http://dx.doi.org/10.1021/cm031124o.
  42. M.P. Hehlen, S.R. Luthi, W.K. Bischel, M.J.F. Digonnet, "Multi-port EDFA for banded-channel amplification," OSA Trends in Optics and Photonics, Optical Amplifiers and Their Applications, 77 (2002) 25-30. http://www.opticsinfobase.org/viewmedia.cfm?uri=OAA-2002-JW6&seq=0.
  43. A. Kuditcher, B.G. Hoover, M.P. Hehlen, E.N. Leith, S.C. Rand, M.P. Shih, ”Ultrafast, cross-correlated harmonic imaging through scattering media”, Appl. Opt. 40 (2001) 45. http://dx.doi.org/10.1364/AO.40.000045.
  44. A. Kuditcher, M.P. Hehlen, C.M. Florea, K.W. Winick, S.C. Rand, “Intrinsic bistability of luminescence and stimulated emission in Yb- and Tm-doped glass”, Phys. Rev. Lett. 84 (2000) 1898. http://dx.doi.org/10.1103/PhysRevLett.84.1898.
  45. M. Pollnau, D.R. Gamelin, S.R. Lüthi, H.U. Güdel, M.P. Hehlen, “Power dependence of upconversion luminescence in lanthanide and transition-metal ion systems”, Phys. Rev. B 61 (2000) 3337. http://dx.doi.org/10.1103/PhysRevB.61.3337.
  46. M.P. Hehlen, A. Kuditcher, A. Lenef, H. Ni, Q. Shu, S.C. Rand, J. Rai, S. Rai, “Non-radiative dynamics of avalanche upconversion in YLiF4:Tm3+”, Phys. Rev. B 61 (2000) 1116. http://dx.doi.org/10.1103/PhysRevB.61.1116.
  47. M.L.F. Phillips, M.P. Hehlen, K. Nguyen, J.M. Sheldon, N.J. Cockroft, "Upconversion Phosphors: Recent advances and new applications", Phys. Chem. Lum. Mater., 99 (2000) 123.
  48. M.P. Hehlen, A. Kuditcher, S.C. Rand, S.R. Lüthi, “Site-selective, intrinsically bistable luminescence of Yb3+ ion pairs in CsCdBr3”, Phys. Rev. Lett. 82 (1999) 3050. http://dx.doi.org/10.1103/PhysRevLett.82.3050.
  49. S.R. Lüthi, H.U. Güdel, M.P. Hehlen, “Influence of the chemical environment on the electronic structure and spectroscopic properties of Er3+ doped Cs3Lu2Cl9, Cs3Lu2Br9, and Cs3Lu2I9“, J. Chem. Phys. 110 (1999) 12033. http://link.aip.org/link/doi/10.1063/1.479139.
  50. S.R. Lüthi, M. Pollnau, H.U. Güdel, M.P. Hehlen, “Near-infrared to visible upconversion in Er3+-doped Cs3Lu2Cl9, Cs3Lu2Br9, and Cs3Lu2I9 excited at 1.54mm”, Phys. Rev. B 60 (1999) 162.  http://dx.doi.org/10.1103/PhysRevB.60.162.  
  51. S.R. Lüthi, H.U. Güdel, M.P. Hehlen, J.R. Quagliano, “Electronic energy-level structure, correlation crystal-field effects, and f-f transition intensities of Er3+ in Cs3Lu2Cl9“, Phys. Rev. B 57 (1998) 15229. http://dx.doi.org/10.1103/PhysRevB.57.15229.
  52. S.R. Lüthi, M.P. Hehlen, T. Riedener, H.U. Güdel, “Excited-state dynamics and optical bistability in the dimer system Cs3Lu2Br9:Yb3+”, J. Lumin. 76&77 (1998) 447.                               http://dx.doi.org/10.1016/S0022-2313(97)00233-0.
  53. M.P. Hehlen, A. Kuditcher, S.C. Rand, M.A. Tischler, “Electron-phonon interactions in CsCdBr3:Yb3+”, J. Chem. Phys. 107 (1997) 4886. http://dx.doi.org/10.1063/1.474851.   
  54. M.P. Hehlen, T.R. Gosnell, N.J. Cockroft, A.J. Bruce, “Spectroscopic properties of Er3+ and Yb3+ doped sodalime silicate and aluminosilicate glasses”, Phys. Rev. B 56 (1997) 9302. http://dx.doi.org/10.1103/PhysRevB.56.9302.
  55. M.P. Hehlen, N.J. Cockroft, T.R. Gosnell, A.J. Bruce, A. Shmulovich, G. Nykolak, “Uniform upconversion in high-concentration Er3+-doped soda-lime and alumino-silicate glasses”, Opt. Lett. 22 (1997) 772. http://dx.doi.org/10.1364/OL.22.000772.
  56. M.P. Hehlen, “Reabsorption artifacts in measured excited-state lifetimes of solids”, J. Opt. Soc. Am. B 14 (1997) 1312. http://dx.doi.org/10.1364/JOSAB.14.001312.
  57. M.P. Hehlen, H.U. Güdel, Q. Shu, S.C. Rand, “Cooperative optical bistability in the dimer system Cs3Y2Br9:10%Yb3+”, J. Chem. Phys. 104 (1996) 1232. http://dx.doi.org/10.1063/1.471532.
  58. M.P. Hehlen, “Effect of radiation trapping on measured excited-state lifetimes in solids”, Trends Opt. Phot., 1 (1996) 530.                                                    http://www.opticsinfobase.org/viewmedia.cfm?uri=ASSL-1996-SM16&seq=0.
  59. M.P. Hehlen, T.R. Gosnell, N.J. Cockroft, A.J. Bruce, W.H. Grodkiewicz, G. Nykolak, J. Shmulovich, R. Gosh, M.R.X. Barros, “Yb3+,Er3+ codoped silica-based glasses for planar optical waveguide amplifiers”, Trends Opt. Phot., 1 (1996) 488.                              http://www.opticsinfobase.org/viewmedia.cfm?uri=ASSL-1996-SM7&seq=0.
  60. M.P. Hehlen, H.U. Güdel, J.R. Quagliano, “Electronic energy-level structure and correlation crystal-field effects of Er3+ in Cs3Lu2Br9“, J. Chem. Phys. 101 (1994) 10303. http://dx.doi.org/10.1063/1.467910.
  61. M.P. Hehlen, G. Frei, H.U. Güdel, “Dynamics of visible-to-infrared upconversion in Cs3Lu2Br9:1%Er3+”, Phys. Rev. B 50 (1994) 16264. http://dx.doi.org/10.1103/PhysRevB.50.16264.
  62. M.P. Hehlen, H.U. Güdel, Q. Shu, J. Rai, S. Rai, S.C. Rand, “Cooperative bistability in dense, excited atomic systems”, Phys. Rev. Lett. 73 (1994) 1103. http://dx.doi.org/10.1103/PhysRevLett.73.1103.
  63. M.P. Hehlen, K. Krämer, H.U. Güdel, R.A. McFarlane, R.N. Schwartz, “Upconversion in Er3+ dimer systems: Trends within the series Cs3Er2X9 (X=Cl,Br,I)”, Phys. Rev. B 49 (1994) 12475. http://dx.doi.org/10.1103/PhysRevB.49.12475.
  64. M.P. Hehlen, K. Krämer, H.U. Güdel, “NIR to VIS/UV upconversion in Cs3Er2X9 (X=Cl,Br,I)”, J. Lumin. 60&61 (1994) 142. http://dx.doi.org/10.1016/0022-2313(94)90115-5.
  65. M.P. Hehlen, H.U. Güdel, “Optical spectroscopy of the dimer system Cs3Yb2Br9”, J. Chem. Phys. 98 (1993) 1768. http://dx.doi.org/10.1063/1.464265.
  66. M.P. Hehlen, H. Riesen, H.U. Güdel, “Synthesis and spectroscopic properties of praseodymium (III) acetate hydrate”, Inorg. Chem. 30 (1991) 2273. http://dx.doi.org/10.1021/ic00010a010.
  67. M.P. Hehlen, H.U. Güdel, “Synthesis and spectroscopic properties of praseodymium acetate monohydrate”, Eur. J. Solid State Inorg. Chem. 28 (1991) 131.

Conference Proceedings and Presentations:

  1. S.R. Tornga, D.T. Wakeford, J.C. Adams, O.C. Trautschold, M.P. Hehlen, “Improved scintillation detector performance using dye-doped coatings”, IEEE Nuclear Science Symposium, Strasbourg, France, November 2016.
  2. A. Junghans, N.R. Weisse-Bernstein, K. Baldwin, R. Lafler, N. Phan, D. Loomba, M.P. Hehlen, ”Superconducting Nuclear Recoil Sensor for Directional Dark Matter Detection”, Applied Superconductivity Conference, Denver, CO, September 2016.
  3. D.T. Wakeford, S.R. Tornga, M.P. Hehlen, “Scintillator Performance with a Method of Enhanced Layered Coatings”, IEEE SORMA West, Berkeley, CA, May 22-26, 2016.
  4. E.R. Meyer, M.P. Hehlen, B. Barker, L.A. Collins, X.X. Zhao, “Uranium doped LiSAF as a precursor for a 229Th nuclear clock experiment”, APS Division of Atomic, Molecular, and Optical Physics (DAMOP), Providence, RI, May 23-27, 2016. 
  5. A. Junghans, N. Weisse-Bernstein, K. Baldwin, R. Lafler, N. Phan, D. Loomba, M.P. Hehlen, ”Directional Dark Matter Detection using Superconducting Nuclear Recoil Sensors”, APS March Meeting, Baltimore, MD, March 2016.
  6. M.P. Hehlen, K.D. Ianakiev, M. Iliev, T.C. Lin, M.T. Barker, M.T. Swinhoe, A. Favalli, “Simulation of light transport in a thermal neutron detector”, 2015 Nuclear Science Symposium, N2B3: Neutron Detectors: Thermal Capture Scintillation Detectors, San Diego, CA, November 3, 2015.
  7. A. Junghans, N. Weisse-Bernstein, K. Baldwin, R. Lafler, N. Phan, D. Loomba, M.P. Hehlen, ”Superconducting Nuclear Recoil Sensor for Directional Dark Matter Detection”, APS Four Corners Meeting, Tempe, AZ, October 2015.
  8. S.D. Melgaard, A. Albrecht, M.P. Hehlen, D.V. Seletskiy, M. Sheik-Bahae, "Optical refrigeration cools below 100 K", Invited, Laser Refrigeration of Solids VIII, SPIE Photonics West, San Francisco, February 11, 2015
  9. W.L. Boncher, E. Judge, J.-M. Sansinena, M.R. Dirmyer, M.P. Hehlen, "Purification of precursors of Yb3+-doped YLF crystals by solvent extraction and electrochemical processing", Invited, Laser Refrigeration of Solids VIII, SPIE Photonics West, San Francisco, February 11, 2015.
  10. M.P. Hehlen, W.L. Boncher, S.P. Love, "Design study of a laser-cooled infrared sensor", Invited, Laser Refrigeration of Solids VIII, SPIE Photonics West, San Francisco, February 11, 2015.
  11. K.D. Ianakiev, M.P. Hehlen, M.T. Swinhoe, A. Favalli, M.L. Iliev, M.T. Barker, B.L. Bennett, “Neutron Detector with Separated Neutron and Gamma Distributions Based on 6Li Glass Scintillator Particles”, Workshop on He-3 Alternatives for International Safeguards, JRC-Ispra (Italy), October 15, 2014.
  12. M. P. Hehlen, “Fundamentals of rare-earth spectroscopy”, University of New Mexico Summer Short Course, PHYC 500.045, July 29 & 30, 2014.
  13. W.L. Boncher, T.C. Lin, M.P. Hehlen, “Development of nanocomposite scintillators for radiation detection”, Gordon Research Conference on Radiation Chemistry, Andover, NH, July 2014.
  14. S.D. Melgaard, A. Albrecht, M.P. Hehlen, D.V. Seletskiy, M. Sheik-Bahae, “Optical refrigeration cools below 100 K”, CLEO: 2014, OSA Technical Digest (online) (Optical Society of America, 2014), paper FTh4D.4.
  15. R.I. Epstein, M. Sheik-Bahae, M.P. Hehlen, “Optical cryocoolers outshine thermoelectrics”, Invited, Session on Emerging Cryogenic Coolers (Infrared Technology and Applications XL), SPIE DSS Defense + Security, Baltimore, May 7, 2014.
  16. M.P. Hehlen, M. Sheik-Bahae, S.D. Melgaard, R.I. Epstein, “Lanthanide-doped materials for solid-state optical refrigeration”, Invited, Session on Emerging Cryogenic Coolers (Infrared Technology and Applications XL), SPIE DSS Defense + Security, Baltimore, May 7, 2014.
  17. K.D. Ianakiev, M.P. Hehlen, M. T. Swinhoe, A. Favalli, M. L. Iliev, T.C. Lin, “Neutron Detector based on particles of 6Li Glass Scintillator Dispersed in Organic Lightguide Matrix”, SORMA 2014.
  18. M.P. Hehlen, W.L. Boncher, S.D. Melgaard, M.W. Blair, R.A. Jackson, T.E. Littleford, S.P. Love, “Preparation of high-purity LiF, YF3, and YbF3 for laser refrigeration”, Invited, Laser Refrigeration of Solids VII, SPIE Photonics West, San Francisco, February, 2014.
  19. W.L. Boncher, M.P. Hehlen, R.E. Muenchausen, “Development of nanocomposite gamma-ray scintillators”, MRS Fall Meeting, Boston, MA, December 2013.
  20. M.P. Hehlen, G.R. Parker, A.M. Novak, P. Rae, G. Rivera, D.W. Schmidt, K.C. Henderson, B.M. Patterson, L.B. Smilowitz, “Fiber-optic point measurement of high pressures in thermal explosions”, CTu2H.6, Conference on Lasers and Electro-Optics (CLEO), San Jose, CA, June 2013.
  21. M.P. Hehlen, “Fundamentals of rare-earth spectroscopy”, Invited, 3½ hour short course presented at the Phosphor Global Summit, New Orleans, March 18, 2013.
  22. M.P. Hehlen, A.H. Mueller, N.R. Weisse-Bernstein, R.I. Epstein, “Electrocaloric refrigerator using electrohydrodynamic flows in dielectric fluids”, Invited, Laser Refrigeration of Solids VI, SPIE Photonics West, San Francisco, February, 2013.
  23. M.P. Hehlen, L.B. Smilowitz, G.R. Parker, A.M. Novak, M.D. Holmes, K.C. Henderson, G. Rivera, D.W. Schmidt, “Measuring Pressure and Temperature inside a Thermal Explosion”, LDRD Day 2013, Pojoaque, NM, October 2012.
  24. A.H. Müller, N.R. Weisse-Bernstein, M. Yazdani, R.I. Epstein, M.P. Hehlen “Thin-film heat switch based on electrohydrodynamic flow in a dielectric fluid”, PRiME 2012, 222nd Meeting of the Electrochemical Society, Honolulu, HI, October 2012.
  25. M.P. Hehlen, B.W. Asay, G.R. Parker, L.B. Smilowitz, B.F. Henson, “Fiber-optic measurement of high temperatures with sub-millimeter spatial resolution”, Conference on Lasers and Electro-Optics (CLEO), San Jose, CA, May 2012.
  26. K. Page, M.P. Hehlen, A. Labouriau, L. Brown, “Precipitation and growth of nanostructured LaF3 in glass ceramics”, Materials Research Society Spring Meeting, April 2011.
  27. W.G. Rellergert, S.T. Sullivan, D. DeMille, R.R. Greco, M.P. Hehlen, R.A. Jackson, J.R. Torgerson, E.R. Hudson, “Progress towards fabrication of 229Th-doped high energy band-gap crystals for use as a solid-state optical frequency reference”, IOP Conference Series: Materials Science and Engineering 15 (2010) 012005.
  28. M.P. Hehlen, “Crystal-field effects in fluoride crystals for optical refrigeration”, Invited, Laser Refrigeration of Solids III, SPIE Photonics West, February, 2010.
  29. M.P. Hehlen, “Novel materials for laser refrigeration”, Laser Refrigeration of Solids II, SPIE Photonics West, February, 2009.
  30. W.M. Patterson, M.P. Hehlen, M. Sheik-Bahae, R.I. Epstein, “Synthesis and evaluation of ultra-pure, rare-earth-doped glass for laser refrigeration”, Laser Refrigeration of Solids II, SPIE Photonics West, February, 2009.
  31. M.P. Hehlen, R.I. Epstein, W.M. Patterson, “Synthesis of ultrapure ZBLAN glass for laser refrigeration”, Laser Refrigeration of Solids I, SPIE Photonics West, February, 2008.
  32. J. Ma, S. Chang, J.Q. Yan, F. Trouw, M.P. Hehlen, R.J. McQueeney, “Effect of Charge Ordering on Phonon Spectra of La1/3Sr2/3FeO3-d”, American Physical Society Meeting, Denver, CO, March 2007.
  33. S. Chang , P. Karen , M.P. Hehlen , F.R. Trouw , R.J. McQueeney, “Inelastic neutron scattering study of the Verwey transition in YBaCo2O5“, American Physical Society Meeting, Denver, CO, March 2007.
  34. M.P. Hehlen, R.I. Epstein, “Ultrapure ZBLAN Glass for Optical Refrigerators”, SPIE Photonics West, February, 2007.
  35. M.P. Hehlen, R.I. Epstein, H. Inoue, “Laser Cooling of Rare-Earth-Doped Solids: The Next Step”, SPIE Photonics West, February, 2006.
  36. M.P. Hehlen, “High Purity ZBLAN:Yb3+ for Laser Cooling: Material Growth and Modeling”, 5th Annual Workshop on Laser Cooling of Solids, Albuquerque, NM, October 2006.
  37. K.T. Tait, F.R. Trouw, M.P. Hehlen, A. Shapiro, Y. Zhao, R.T. Downs, “Inelastic Neutron Scattering Studies of THF+H2 Clathrates”, International Mineralogical Association meeting, Kobe, Japan, 2006.
  38. M.P. Hehlen, “Ultrapure ZBLAN:Yb3+ Glass for Optical Refrigeration”, 4th Annual Workshop on Laser Cooling of Solids, Albuquerque, NM, June 2005.
  39. S. Chang, P. Karen, M.P. Hehlen, F.R. Trouw, W.P. Beyerman, R.J. McQueeney, “Inelastic neutron scattering study of the magnon density-of-states of YBaFe2O5”, International Conference on Neutron Scattering, Sydney, Australia, 2005.
  40. A.D. Christianson, J.M. Lawrence, N.O. Moreno, E.D. Bauer, E.A. Goremychkin, C.H. Booth, J.L. Sarrao, J.D. Thompson, A.Lobos, A.A. Aligia, C.D. Batista, F.R. Trouw, M.P. Hehlen, “Anisotropic Behavior in Intermediate Valence Yb2M3Ga9 (M = Rh, Ir)”, APS Meeting, March 2005.
  41. M.P. Hehlen, F.R. Trouw, J.T. Mang, R.M. Laine, “Acoustic mode confinement in nano-crystalline yttria”, American Conference on Neutron Scattering, College Park, MD, 2004.
  42. A.D. Christianson, E.D. Bauer, J.M. Lawrence, P.S. Riseborough, N.O. Moreno, P.G. Pagliuso, J.L. Sarrao, J.D. Thompson, M.P. Hehlen, F.R. Trouw, E.A. Goremychkin, R.J. McQueeney, “Crystalline electric field effects in CeMIn5: Superconductivity and the influence of Kondo spin fluctuations”, American Conference on Neutron Scattering, College Park, MD, 2004.
  43. T. Egami, W. Dmowski, I.K. Jeong, R.H. Heffner, J.S. Park, K.S. Hong, M. Hehlen, F. Trouw, “Temperature dependent dynamic and static correlations in relaxor ferroelectric Pb(Mg1/3Nb2/3)O3”, Conference on Fundamental Physics of Ferroelectrics, Williamsburg, MD, 2004.
  44. W.K. Bischel, M.P. Hehlen, S.R. Lüthi, “Multi-Port EDFAs for Banded-Channel Amplification”, IEEE Lasers & Electrooptics Society (LEOS) Conference, 2003.
  45. A. Kuditcher, M.P. Hehlen, C.M. Florea, K.W. Winick, S.C. Rand, “Intrinsic multistability of Yb and Tm luminescence and stimulated emission in oxide glass”, Quantum Electronics and Laser Science Conference, Baltimore, 1999.
  46. A. Kuditcher, M.P. Hehlen, S.C. Rand, B. Hoover, E. Leith, “Time-gated harmonic imaging through scattering media”, Conference on Lasers and Electro-Optics, San Francisco, 1998.
  47. M.P. Hehlen, S.R. Lüthi, H.U. Güdel, “Intense visible upconversion luminescence from Cs3Lu2X9:Er3+ (X=Cl,Br,I) excited at 1.5 mm”, Conference on Lasers and Electro-Optics, San Francisco, 1998.
  48. M.P. Hehlen, S.C. Rand, “Electron-Phonon Coupling in CsCdBr3:Yb3+”, 11th International Conference on Dynamical Processes in Excited States of Solids (DPC), Mittelberg, Germany, 1997.
  49. M.P. Hehlen, G. Frei, H.U. Güdel, “Dynamics of infrared-to-visible upconversion in Cs3Lu2Br9:1%Er3+”, Quantum Electronics and Laser Science Conference, Baltimore 1995.
  50. M.P. Hehlen, “Cross relaxation of excited states in a one-dimensional compound”, 10th Course of the International School of Atomic and Molecular Spectroscopy, Erice (Italy), 1991; NATO Advanced Science Institutes Series B, Physics, 301 (1992) 704.
  51. M.P. Hehlen, “Cross relaxation of excited states in a one-dimensional compound”, NATO Adv. Sci. Inst. Series B 301 (1992) 704.

Other Publications:

  1. M.P. Hehlen, RELIC 1.0 (Rare Earth Level and Intensity Calculations) User Guide, LA-UR-13-23498, Los Alamos National Laboratory, (2013).
  2. M.P. Hehlen, “Cryogenic Goniometer Motion Control Software: User Guide & Software Documentation”, Los Alamos National Laboratory (2004), LA-UR-04-8318
  3. Markus Hehlen, “Mit Laserlicht zur kontrollierten Kernfusion”, Neue Zürcher Zeitung, November 27, 2002
  4. Markus Hehlen, “Zwei Sonden auf dem Weg zum Rande des Sonnensystems”, Neue Zürcher Zeitung, September 25, 2002
  5. H.U. Güdel, M.A. Aebersold, M.P. Hehlen, A. Furrer, R. Kahn, “Exchange interactions in dimers of rare-earth and transition metal ions: Magnetic excitations in YbHoBr9, YbFeBr9, and YbTiBr9”, Exptl. Report 1992, Laboratoire Leon Brilloiun (LLB), CEN Saclay, France.