Acta Photonica Sinica, Volume. 44, Issue 8, 819001(2015)
Optical and Second Harmonic Properties in Al,S and Te Doped GaSe Crystals
The transparency and second harmonic properties of Al,S and Te doped GaSe crystals were studied.Low absorption coefficients of α≤0.1~0.2 cm-1 are found in crystals with suitable doping level in transparent range which can be used in nonlinear devices.High doping level is allowed in GaSe:S crystals whose transparency spectra shift towards to short-wavelength range.The short wavelength transparency cut-off of both Al and Te doped crystals shifts more slowly than S doped crystals towards to opposite direction.The optical quality of the crystals has declined markedly when the doping concentration up to GaSe:Al (0.5 mass%) and GaSe:Te (5 mass%).The phase matching curves shift towards to short-wavelength and output power is significantly higher in S doped GaSe crystals than that in pure GaSe crystals with fs Ti:Sapphire laser and CO2 laser pumping.The optimal doping concentration is ascertained as 2 mass%.No obvious differences of type I second harmonic phase matching angle between Al,Te doped and pure crystals are found.The experimental results are in good agreement with theoretical curve.GaSe:Te crystals are found to possess the hexagonal structure like ε-GaSe when the doping concentration is no more than 5 mass% with nonlinear method.The SHG efficiency ratio of the optimal doped crystals GaSe:Al (0.1 mass%),GaSe:S (2 mass%) and GaSe:Te (0.5 mass%) is about 1:0.6:0.5 under CO2 laser pumping.GaSe:S (2 mass%) crystal shows the best performance whose efficiency is about 3 times higher than that in pure GaSe among all used samples.
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FENG Zhi-shu, LI Xiao-ming, YU Dan, KANG Zhi-hui, GAO Jin-yue. Optical and Second Harmonic Properties in Al,S and Te Doped GaSe Crystals[J]. Acta Photonica Sinica, 2015, 44(8): 819001
Received: Feb. 15, 2015
Accepted: --
Published Online: Sep. 8, 2015
The Author Email: Zhi-shu FENG (zhishu_feng@163.com)