Right-angle prism resonance cavity-based broadband terahertz wave radiation source

Abstract

The invention discloses a right-angle prism resonance cavity-based broadband terahertz wave radiation source. A resonance cavity consists of two right-angle prisms, and inclined planes of the right-angle prisms are taken as light transmitting surfaces; a MgO:LiNbO3 crystal is arranged in the resonance cavity, and a silicon prism array is arranged on the surface of the MgO:LiNbO3 crystal; pump light is transmitted into the resonance cavity, forms an included angle of 1.5DEG with the cavity axis of the resonance cavity, and does not pass through the two right-angle prisms; and the pump light excites the MgO:LiNbO3 crystal to generate broadband terahertz waves and broadband Stokes light oscillating in the resonance cavity, and the broadband Stokes light is transmitted through the silicon prism array. The right-angle prism resonance cavity-based broadband terahertz wave radiation source is a broadband all solid terahertz wave coherent radiation source with advantages of high energy, high efficiency, small volume, simple structure and low price, and can be widely applied to the technical fields of terahertz optoelectronics, such as medical diagnosis, precision spectral analysis, biomedical imaging, terahertz communication and the like.

Description

technical field [0001] The invention relates to the technical field of terahertz wave optoelectronics, in particular to a broadband terahertz wave radiation source based on a rectangular prism resonant cavity. Background technique [0002] Terahertz waves refer to electromagnetic waves with frequencies in the range of 0.1-10THz (1THz=10 12 Hz), its wave band is between millimeter wave and far infrared light in the electromagnetic spectrum. Since the emission, reflection and transmission spectra of substances in the terahertz wave band contain rich physical and chemical information, and terahertz wave radiation has the characteristics of low energy and high penetration, it is widely used in various basic research fields and applications. All research areas have great scientific research value and broad application prospects. In recent years, as an emerging optoelectronic technology - terahertz wave optoelectronic technology has developed rapidly, and has become a research h...

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Problems solved by technology

However, the femtosecond laser, the excitation source required for this broadband terahertz wave radiation source, is expensive and cumbersome to maintain, and its output stability directly determines the bandwidth characteristics of the excited terahertz wave radiation, and the generated Terahertz waves have poor spatial directionality, large divergence angles, and low output energy. It is necessary to use time delay lines, lock-in amplifiers and other equipment for indirect detection, which makes the detection system not only complicated to operate, but also large in size and fast in detection speed. slow

[0005] Although the Terahertz-wave Parametric Generator (TPG) based on the stimulated electromagnetic coupler scattering process can also generate broadband Terahertz wave radiation with relatively good directivity, the one-way gain parameter The process leads to a high threshold of terahertz wave generation, and the three-wave conversion efficiency and output energy of terahertz wave are very low.

Although it can be achieved by using multiple nonlinear crystals (such as LiNbO 3 Crystal or MgO:LiNbO 3 Crystal) cascaded to increase the gain length, and increase the output energy of the terahertz wave by increasing the pump energy, but this is easy to cause optical damage to the crystal, and the effect of increasing the output energy of the terahertz wave is not obvious

By adding a resonant cavity to the TPG to form a Terahertz-wave Parametric Oscillator (Terahertz-wave Parametric Oscillator--TPO), the resonant cavity is generally a flat-flat cavity structure, which can greatly reduce the terahertz wave The threshold value of generation can be increased to increase its output energy, but what is produced at this time is a kind of terahertz wave radiation with extremely narrow line width and close to single frequency

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