Ultrafast non-linear optical properties of Ge20As25Se55 chalcogenide films

✍ Scribed by Qiming Liu; Bing Lu; Xiujian Zhao; Fuxi Gan; Jun Mi; Shixiong Qian

• Publisher: Elsevier Science
• Year: 2006
• Tongue: English
• Weight: 173 KB
• Volume: 258
• Category: Article
• ISSN: 0030-4018
• DOI: 10.1016/j.optcom.2005.07.045

✦ Synopsis

The non-resonant third-order non-linear optical properties of amorphous Ge 20 As 25 Se 55 films were studied experimentally by the method of the femtosecond optical heterodyne detection of optical Kerr effect. The real and imaginary parts of complex third-order optical non-linearity could be effectively separated and their values and signs could be also determined, which were 6.6 • 10 À12 and À2.4 • 10 À12 esu, respectively. Amorphous Ge 20 As 25 Se 55 films showed a very fast response in the range of 200 fs under ultrafast excitation. The ultrafast response and large third-order non-linearity are attributed to the ultrafast distortion of the electron orbitals surrounding the average positions of the nucleus of Ge, As and Se atoms. The high third-order susceptibility and a fast response time of amorphous Ge 20 As 25 Se 55 films makes it a promising material for application in advanced techniques especially in optical switching.