Cost-effective multi-dimensional imaging of terahertz pulses via compact CMOS sensor cameras

Terahertz radiation can be generated through a small variety of methods for a wide range of applications including noninvasive hyperspectral imaging, electronic switching, and vibrational excitation of materials. Generation of frequencies ranging between 0.1 and 10 THz is possible through optical rectification of ultra-fast infrared laser pulses. While detection of a small THz spot size is simple, recording the complete beam profile in space and time can be more complex. Current technology used for multi-dimensional imaging of THz beams and particularly their frequency spectra is relatively expensive and therefore less accessible for both public and private use. We propose an inexpensive and compact setup for this type of imaging using a common CMOS camera for electro-optic sampling. We generate broadband THz from 0.1 to 5 THz using an infrared Ti:Sapphire laser to pump organic nonlinear optical crystals and use an 800 nm probe to detect the resulting electric field. We then project the subsequent probe pulse onto the common CMOS camera to construct a 3D model of the THz beam as both a function of time and a function of frequency. Funding: NSF-DMR 2104317