Stimulated Raman scattering in natural crystals of fluorapatite, Ca5(PO4)3F. Issue 5 (9th September 2016)

• Record Type: Journal Article
• Authors: Kaminskii, Alexander A.; Bohatý, Ladislav; Lux, Oliver; Rhee, Hanjo; Eichler, Hans Joachim; Libowitzky, Eugen; Kleinschrodt, Reiner; Yoneda, Hitoki; Shirakawa, Akira; Becker, Petra
• Is Part Of: Laser & photonics reviews. Volume 10:Issue 5(2016:Sep.)
• Page Start: 814
• Page End: 825
• Publication Date: 2016-09-09
• Subjects: fluorapatite -- Ca5(PO4)3F -- stimulated Raman scattering (SRS) -- Stokes and anti‐Stokes frequency comb -- natural SRS‐active crystals; Lasers -- Periodicals; Photonics -- Periodicals; Lasers -- Périodiques; Photonique -- Périodiques; 621.36
• DOI: 10.1002/lpor.201600100
• Languages: English
• ISSNs: 1863-8880

Abstract

Abstract : The authors demonstrate stimulated Raman scattering in crystals of fluorapatite, Ca5 (PO4 )3 F, a laser host material which had unjustly fallen into oblivion in recent years. Picosecond laser excitation of this crystal generates a multitude of Stokes and anti‐Stokes spectral lines ranging from the UV to the NIR spectral region, thus indicating large potential for Raman frequency conversion. The work also includes a review of previous studies on SRS in natural crystals. Abstract: Hexagonal Ca5 (PO4 )3 F, known as natural crystal fluorapatite and oldest host‐crystal for Ln 3+ ‐lasant ions, is presented as a Raman‐active material. High‐order Raman‐induced χ (3) ‐nonlinear processes are discovered in natural crystals of fluorapatite under picosecond pumping at 1.064 μm and 0.532 μm wavelength. A multitude of Stokes and anti‐Stokes components is generated in the ultraviolet, visible and near‐infrared spectral region by stimulated Raman scattering (SRS) and Raman four‐wave mixing (FWHM), resulting in a frequency comb with a width of 520 THz. The spectral lines are identified and attributed to the ν1 (Ag ) vibration mode of the tetrahedral [PO4 ] units which is related to a Raman shift of ωSRS ≈ 965 cm −1 . The first Stokes steady‐state Raman gain coefficient in the near‐infrared spectral range is estimated to be >0.38 cm·GW −1 . Finally, a short review of SRS‐promoting vibration modes and observed χ (3) ‐ nonlinear interactions in all known SRS‐active natural crystals (minerals) is given.