Spectroscopic evaluation of Tm-doped potassium lead halides for 2μm laser cooling applications

Tm3+ doped solids have shown promising results for laser cooling applications at IR wavelengths of ~2 μm. The extended IR fluorescence of the involved Tm3+ transition (3H6 → 3F4), however, requires low-phonon energy hosts reducing the detrimental effect of non-radiative decay through multiphonon relaxation. In this work the temperature dependent absorption and emission properties of Tm doped KPC (hνmax<200 cm-1) and KPB (hνmax<140 cm-1) crystals were evaluated for applications in laser cooling. Under laser pumping both crystals exhibited broad IR fluorescence at room temperature with a mean fluorescence wavelength of 1.82 μm and bandwidth of 0.14 μm (FWHM). Initial experiments on laser-induced heating and cooling were performed using a combined IR imaging and fluorescence thermometry setup. Employing a continuous-wave laser operating at 1.907 μm, Tm: KPC and Tm: KPB crystals revealed a very small heat load resulting in a temperature increase of ~0.3 (±0.1) °C compared to undoped reference samples. Further work on material improvement will be necessary to identify possible non-radiative loss mechanisms and to improve the crystal quality.

[1]  C. Mungan,et al.  New materials for optical cooling , 2000 .

[2]  Yang Shen,et al.  Temperature sensing with fluorescence intensity ratio technique in epoxy-based nanocomposite filled with Er3+-doped 7YSZ , 2012 .

[3]  J. Adam,et al.  Anti-Stokes laser-induced internal cooling of Yb 3+ -doped glasses , 2000 .

[4]  Epstein,et al.  Observation of anti-stokes fluorescence cooling in thulium-doped glass , 2000, Physical review letters.

[5]  Mansoor Sheik-Bahae,et al.  Optical refrigeration to 119 K, below National Institute of Standards and Technology cryogenic temperature. , 2013, Optics letters.

[6]  Lloyd L. Chase,et al.  Infrared cross-section measurements for crystals doped with Er/sup 3+/, Tm/sup 3+/, and Ho/sup 3+/ , 1992 .

[7]  Qihua Xiong,et al.  Laser cooling of a semiconductor by 40 kelvin , 2013, Nature.

[8]  Mansoor Sheik-Bahae,et al.  Recent progress in laser cooling via resonant cavity , 2009, OPTO.

[9]  D N Payne,et al.  Spectroscopic data of the 1.8-, 2.9-, and 4.3-microm transitions in dysprosium-doped gallium lanthanum sulfide glass. , 1996, Optics letters.

[10]  V. K. Rai,et al.  Fluorescence intensity ratio technique for Sm3+ doped calibo glass. , 2008, Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy.

[11]  S. Trivedi,et al.  Material purification, crystal growth, and spectroscopy of Tm-doped KPb2Cl5 and KPb2Br5 for 2 µm photonic applications , 2014 .

[12]  Byoungho Lee,et al.  Temperature-dependent fluorescence characteristics of an ytterbium-sensitized erbium-doped silica fiber for sensor applications , 2006 .

[13]  A. Burger,et al.  Growth and characterization of Er-doped KPb2Cl5 as laser host crystal , 2003 .

[14]  Mansoor Sheik-Bahae,et al.  Precise determination of minimum achievable temperature for solid-state optical refrigeration , 2013 .

[15]  Joseph J. Brown,et al.  Measurements of optical refrigeration in ytterbium-doped crystals , 2001 .

[16]  S. Trivedi,et al.  Crystal growth and optical properties of Dy-doped potassium lead bromide (KPb2Br5) , 2006 .

[17]  Mansoor Sheik-Bahae,et al.  Optical refrigeration : science and applications of laser cooling of solids , 2009 .

[18]  F. Micheron,et al.  Comparison of Peltier and anti-Stokes optical coolings , 2000 .

[19]  Jinsu Zhang,et al.  Laser cooling with optical temperature sensing in Er3+-doped tellurite-germanate glasses , 2013 .

[20]  Mansoor Sheik-Bahae,et al.  Anti-Stokes luminescence cooling of Tm3+ doped BaY2F8. , 2008, Optics express.

[21]  T. R. Gosnell,et al.  Observation of laser-induced fluorescent cooling of a solid , 1995, Nature.

[22]  Markus P. Hehlen,et al.  Novel materials for laser refrigeration , 2009, OPTO.

[23]  Steven R Bowman,et al.  Optical cooling in Er3+:KPb2Cl5. , 2009, Optics Express.