Spectrometer Advances Terahertz Waves Research

Starting October, Hamamatsu Photonics K.K. will market the C16356 handy probe terahertz spectrometer. Terahertz waves are electromagnetic waves around a wavelength of 300μm, which corresponds to a frequency of 1THz. Terahertz waves have intermediate properties between straight-travelling light and radio waves that can travel through objects. 

A terahertz spectrometer is a system that can specify crystallization, moisture content, and other features of samples based on information of each wavelength in the terahertz range absorbed by the samples. 

Research and development into terahertz waves have been underway globally, targeting various sectors, including telecommunications, industrial, and academic research. Terahertz waves enable crystallization, moisture content, and other information of samples that are different from information obtained by conventional spectroscopic analysis using ultraviolet rays, visible light, or infrared light. Hence, Hamamatsu Photonics is engaged in basic and applied research on terahertz waves in the analysis field and has been advancing the commercialization of spectrometers and the development of wavelength boards for terahertz waves. 

C16356 handy probe terahertz spectrometer

Addresses Challenges

At present, the company is manufacturing and selling benchtop spectrometers that use attenuated total reflection (ATR).  However, there have been challenges, including restrictions on the size and state of samples, and the necessity to carry samples into the analysis chamber. 

The C16356 adopts the ART spectroscopy with a separate measurement section, first of its kind in the world. It offers solutions to problems of existing products as terahertz waves are easily absorbed by water in the light transmission method, and the method requires a step to prepare pellets when measuring powders. 

Hamamatsu Photonics has reviewed the optical design of conventional products from scratch using its original optical design technology and terahertz wave technology it has nurtured over many years. The company has created the optical system of the spectrometer using optical fibers and optical communications devices. At the same time, it has also shifted terahertz wave measurement from the traditional electrical method to an optical method.  These efforts have made the measurement unit compact and can be connected to the main unit by an optical fiber. 

Conventional products require samples to be set in the measurement chamber inside the spectrometer. The C16356 enables the measurement unit to be freely moved in accordance with the sample, thereby dramatically improving measurement freedom. By reducing the number of optical components used and electrical wiring to optimize the housing design, the volume of the main unit has been reduced to about 60 percent and weight to about 40 percent of the previous product. Furthermore, the C16356 features enhanced ruggedness against vibrations. It can be carried easily using a carrier case, thus enabling its use for quality management by bringing it into the manufacturing site of drugs, chemicals, and food.