Acta Optica Sinica, Volume. 43, Issue 5, 0519001(2023)
Tunable Broadband Terahertz Wave Generation Based on Optical Rectification Effect of Shaped Ultrashort Laser Pulses Interacting with GaSe Crystal
Terahertz wave refers to the electromagnetic wave whose frequency and wavelength are in the ranges of 0.1-10.0 THz and 30-3000 μm, respectively. Throughout the entire electromagnetic spectrum, the terahertz band is located between electronics and optical bands, so it is also called the "terahertz gap". Terahertz wave has some special properties due to its special band, such as low energy, high penetration, and transient. With the development of research and the maturity of technology, terahertz wave has shown bright application prospects in material science, biomedicine, imaging, and communication in recent years. Broadband terahertz radiation source is an important basis for spectral technology in the terahertz band. Therefore, it is of great significance to develop broadband terahertz radiation sources. Since GaSe crystal has a high light transmission and a small absorption coefficient, it has a good application in the generation and detection of broadband terahertz radiation. In this study, GaSe crystal is used to generate tunable broadband terahertz pulses through the optical rectification effect, which provides new ideas for the generation of tunable broadband terahertz pulse radiation.
In light of nonlinear optics, this paper studies the tunable broadband terahertz radiation generated through the optical rectification effect of shaped ultrashort laser pulses interacting with GaSe crystal, and the process is simulated by numerical calculations. It is found that by adjusting the laser spectrum component with a 4F shaping system, some components whose wavelengths are greater than
The terahertz radiation from GaSe crystal with different pulse durations is given by numerical methods (Fig. 2). Tunable terahertz pulses pumped by the shaped ultrashort laser pulses with a duration of 50 fs and a center wavelength of 800 nm are obtained, and their properties are given in detail. When the cutoff wavelength
In summary, this paper presents a simple way to generate tunable terahertz pulse radiation by using the optical rectification effect of shaped ultrashort laser pulses on the GaSe crystal. The pump laser spectrum component in the 4F shaping system is shielded by an opaque baffle so that the high-peak-power laser pulse can be shaped, and the envelope of the laser pulse and the terahertz spectrum distribution generated by it can be changed. It is found that the center frequency and bandwidth of the generated terahertz pulse can be adjusted by changing the cutoff wavelength. This idea might offer new methods to generate tunable broadband terahertz pulses based on the optical rectification effect of GaSe crystal, which provides a good reference for related experiments.
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Qiangshuang Li, Changming Sun, Shuzhen Fan, Haiwei Du. Tunable Broadband Terahertz Wave Generation Based on Optical Rectification Effect of Shaped Ultrashort Laser Pulses Interacting with GaSe Crystal[J]. Acta Optica Sinica, 2023, 43(5): 0519001
Category: Nonlinear Optics
Received: Aug. 31, 2022
Accepted: Oct. 17, 2022
Published Online: Feb. 27, 2023
The Author Email: Du Haiwei (haiweidu@nchu.edu.cn)