At Photonics West 2024, we are excited to present a series of innovative demonstrations, including sessions on how to use NIR spectroscopy for plastic sorting, exploring hyperspectral imaging with an InGaAs camera, and showcasing cutting-edge gas detection technologies.

How to use NIR spectroscopy for plastic sorting 


In this presentation, Stephanie Butron, Applications Engineer at Hamamatsu Corporation, discusses the use of near-infrared (NIR) spectroscopy in sorting plastics. She explains that while plastics may appear similar to the naked eye, NIR spectroscopy can reveal distinct differences in their composition. The process involves using an NIR light source, such as a tungsten halogen lamp, to illuminate plastic samples. A detector, specifically an MS MEMS FPI (Fabry-Perot Interferometer) spectrometer, measures the reflected NIR light. Each type of plastic exhibits unique spectra in the NIR range, allowing real-time differentiation. Stephanie highlights the applications of this technology in plastic sorting, material identification, authentication, and more. Interested individuals are invited to visit Hamamatsu Corporation's booth at Photonics West to witness the demo and engage with their engineers.

Hyperspectral imaging using InGaAs camera  

Gas detection demonstration 


In this presentation, Gary Spingarn a product manager at Hamamatsu for infrared devices, introduces a gas detection demo for carbon dioxide. The demo showcases a gas detection module that will be featured at Photonics West 2024. The module consists of a 4.3 micron LED, which is a particularly strong absorption line for carbon dioxide, and two InAsSb photodiodes with band-pass filters. One diode is used for measuring carbon dioxide concentration at 4.3 microns, while the other serves as a reference channel at 3.9 microns.


The principle behind this setup is based on absorption and Beer's Law, where carbon dioxide in the environment absorbs some of the emitted light, resulting in a lower signal in the measurement channel. The ratio of these signals directly corresponds to the concentration of carbon dioxide in parts per million (PPM). Gary demonstrates this by introducing his own breath into the space, causing an increase in measured PPM. Conversely, purging the space with atmospheric air returns the carbon dioxide concentration to normal atmospheric levels.


The gas detection module provides real-time measurements, with components that have a long lifetime and low power consumption, making it suitable for environmental and medical applications.