Schematic description for THz generation and Detection:
Terahertz (THz) wave is an electromagnetic wave in the range typically from 100 GHz to 10THz. THz wave sources currently receive strong attention as an alternative light sources for spectroscopy, security screening, medical or biological imaging and nondestructive material control of manufacturing process of soft materials.
Sacher Lasertechnik offers CW THz systems which generate THz waves via photomixing method. The optical seed power to several hundreds mW is available depending on the requirements of users. The following diagram show a schematic description of our THz system.
                            
 
     
Spectrum of high power two color system:
The generated THz radiation corresponds to the beat frequency of the seed laser frequencies. Below graph shows an optical spectrum of two color beam from an amplifier seeded by two tunable diode lasers. The generated THz frequency is varied by changing the beat frequency of two colors.
                     
Temperature tuning of DFB diode laser as a seed laser for THz generation:
The wavelength tuning of DFB lasers with a temperature change allows a mode-hop free wavelength change. The temperature tuning speed strongly depends on the type of the type of packaging of the DFB lasers. A package size with a small thermal load enables a relatively fast tuning frequency in the order of 100mHz.
                   
The graphic shows the rapid temperature tuning of a 780nm DFB laser with a low thermal load package. The temperature change of 10°C results in a wavelength scan of more than 0.4nm.