Hermite-Gaussian laser modulation for optimal THz emission in collisional homogeneous plasma

Terahertz (THz) research has gained prominence because to its diverse practical applications in areas including early cancer detection, oral tissue detection, concealed objects detection, food safety and quality inspection, bacteria detection and burn diagnosis. Several efforts have been made to create a customizable and energy-efficient terahertz (THz) generator. This study examines the concurrent transmission of two Hermite-Gaussian (HG) laser pulses in a collisional homogeneous plasma medium. Laser-plasma interaction exhibits nonlinear characteristics, leading to the production of extremely effective THz radiation. An in-depth investigation is conducted to study the relationship between the efficiency of converting terahertz (THz) waves and various parameters such as plasma frequency, Hermite polynomial mode index (s), and electron collisional frequency. Deviation from the resonant direction leads to a decrease in the efficiency of converting THz waves. Efficiency drops to almost zero when the normalized THz frequency surpasses 1.8 and the normalized collisional frequency goes above 4. This study achieves normalised THz amplitude nearly 0.9 and 0.15 for normalised THz frequency and normalised collisional frequency, respectively. Conversion efficiency in the terahertz band increases with higher Hermite polynomial mode index values for s = 0,1,2. The suggested method efficiently produces powerful, customizable, and energy-saving THz radiation by controlling the Hermite polynomial mode index values.