Anti-Stokes laser-induced cooling in rare-earth doped low phonon materials

Abstract In this work we discuss the anti-Stokes laser-induced cooling of two matrices doped with Yb 3+ and Er 3+ : a low phonon KPb 2 Cl 5 crystal and a fluorochloride glass. In order to assess the presence of internal cooling in these systems we used photothermal deflection and conventional excitation spectroscopic techniques, whereas the bulk cooling in the Er 3+ -doped materials was detected by means of a calibrated thermal sensitive camera. Furthermore, we also consider some of our findings on cooling processes occurring in Yb 3+ -doped low phonon materials from a theoretical perspective. The experimental results are in good agreement with the predictions of a model based on the presence of a second order process in the cooling mechanism. The fluorescence excess shown by the excitation spectra of Yb 3+ -doped sample obtained at high fluences, by pumping at wavelengths in the cooling region, has been explained in the framework of the configurational coordinate model by considering that the frequencies of the vibrational modes in the ground and excited states change at high pumping intensities (quadratic coupling mode). In the case of Er 3+ ion, it is worthwhile to mention that the cooling was observed in the spectral region where some upconversion processes that initiate at the pumped 4 I 9/2 level occur. Together with the spectroscopic characterization, a short discussion on the experimental and theoretical background of the cooling process including the possible influence of upconversion processes is presented.

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

[2]  Agustin Sanchez-Lavega,et al.  Thermal diffusivity measurements on solids using collinear mirage detection , 1993 .

[3]  P. Pringsheim.  Zwei Bemerkungen über den Unterschied von Lumineszenz- und Temperaturstrahlung , 1929 .

[4]  T. R. Gosnell.  Laser cooling of a solid by 65 K starting from room temperature , 1998 .

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

[6]  Alfred Kastler,et al.  Quelques suggestions concernant la production optique et la détection optique d'une inégalité de population des niveaux de quantifigation spatiale des atomes. Application à l'expérience de Stern et Gerlach et à la résonance magnétique , 1950 .

[7]  Clark,et al.  Laser cooling in the condensed phase by frequency up-conversion. , 1996, Physical review letters.

[8]  A. García-Adeva,et al.  Anti-Stokes laser cooling in Yb(3+)-doped KPb(2) Cl(5) crystal. , 2002, Optics letters.

[9]  S. Greenfield,et al.  Advances in Laser Cooling of Thulium-Doped Glass , 2003 .

[10]  A. Boccara,et al.  Photothermal deflection spectroscopy and detection. , 1981, Applied optics.

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

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

[13]  Compositional investigation of Yb3+-doped heavy metal fluoride glasses for laser-induced fluorescent cooling applications , 1999 .

[14]  Rolindes Balda,et al.  Upconversion cooling of Er-doped low-phonon fluorescent solids , 2009 .

[15]  Rolindes Balda,et al.  Anti-stokes laser cooling in bulk erbium-doped materials. , 2006, Physical review letters.

[16]  J. Geusic,et al.  Optical Refrigeration in Nd-Doped Yttrium Aluminum Garnet , 1968 .

[17]  T. R. Gosnell,et al.  Laser cooling of a solid by 65K starting from room temperature. , 1997, Optics letters.

[18]  Steven R. Bowman,et al.  Lasers without internal heat generation , 1999 .

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

[20]  G. Weimann,et al.  Cooling of a semiconductor by luminescence up-conversion , 1999 .

[21]  Ralph H. Page,et al.  Optical properties of Dy 3+ - and Nd 3+ -doped KPb 2 Cl 5 , 2001 .

[22]  B. C. Edwards,et al.  Spectroscopic evaluation of Yb/sup 3+/-doped glasses for optical refrigeration , 1998 .

[23]  J. Etxebarria,et al.  Photoacoustic spectra of transparent solids doped with localised absorbing centres , 1983 .

[24]  R. Summitt,et al.  Optical Interactions in Solids , 1968 .

[25]  T. Keil.  Shapes of Impurity Absorption Bands in Solids , 1965 .

[26]  Rolindes Balda,et al.  Upconversion processes in Er 3 + -doped KPb 2 Cl 5 , 2004 .

[27]  Mauro Tonelli,et al.  Spectroscopic and laser cooling results on Yb3+-doped BaY2F8 single crystal , 2006 .

[28]  S. V. Petrushkin,et al.  Boson Operator Elimination Method in the Laser Cooling of Solids , 2001 .

[29]  Mansoor Sheik-Bahae,et al.  Laser cooling of solids to cryogenic temperatures , 2010 .