A new dual-frequency laser for THz generation

THz waves are today used for Imaging (security) and Spectroscopy. The IPR in France recently demonstrated a new dual-frequency 780 nm Ti:Sa laser optimized for high spectral purity tunable CW-THz generation. Optimization of the dual –frequency laser has been based on real time and high-resolution instrument. For dual-frequency laser, more than one laser peak need to be controlled. If a high resolution laser spectrum analyzer is used, one can control the spacing between the two peaks and their absolute wavelength….

Multimode VCSEL unstability

Practical cases

VCSEL are now used as singlemode and multimode laser sources in many application fields. Many users are not laser expert and may discover VCSEL unstability late in a development …VCSEL Unstability can be related to two mains parameters : drive current and temperature. The following videos can help feeling how sensitive VCSEL unstability can be for a specific application. Here is a video of the spectrum of VCSEL when changing its current from 90 mA to 140 mA. From a…

Monitoring a laser wavelength for strain and temperature

How a laser enables you to monitor temperature and strain variations?

Theoretical knowledge

Lasers are also used in set-ups aimed for monitoring strain and temperature. In those set-ups strain and temperature variations are directly proportional to the shift of a reflected laser wavelength. Optical Fiber Bragg Gratings (FBG) are known for many years and allow using an optical fiber as a Temperature + Strain + Pressure sensor. An optical fiber Bragg grating acts as a mirror at a specific wavelength depending on the distance between its lines, and transmits all others, or acts…