Throughout its history, the semiconductor industry has proved its ability to integrate functions on a chip. These chips can be supplied in very high volumes and at low costs, opening the door for new unprecedented applications and markets in multiple industries.
The spectrometry instrumentation industry is no longer an exception with
MEMS + FT-IR = Neo-Spectra
What’s FT-IR spectroscopy?
Spectroscopy is the study of physical and/or chemical properties of materials by analyzing their response to light. Knowing that each chemical component has a unique spectral pattern, the analysis of the spectral response of matters tells a lot about their chemical composition and/or concentration. Today, spectrometer instruments can be found in labs and industrial environments for material identification and/or quantification in different application areas. There are many conventional topologies for spectrometry instrumentation including Fourier Transform InfraRed (FT-IR) that offers several performance and cost advantages.
What’s MEMS ?
Micro Electro Mechanical Systems (MEMS) are chip-based electro mechanical elements that are developed with techniques inherited from the semiconductor microfabrication technologies. Electro mechanical designs are first printed on masks, these masks are used to pattern the design over silicon wafers by photolithography, the patterns are then etched using batch processes, and finally chips are diced and packaged. Over the last decades, MEMS chips revolutionized several industries to the point that, today, MEMS chips can be found in a multitude of electronic devices.
How does FT-IR work?
The core of any FT-IR spectrometer is a two-beam optical interferometer named the Michelson interferometer. A beamsplitter splits the incident beam into two paths: one of the beams is reflected by a moving mirror, and the other is used as a reference when reflected by a fixed mirror. The moving mirror controls the optical path, or simply the delay, of the first beam and thus the two reflected beams interfere producing a pattern that corresponds to the spectral content of the input light. The latter is captured by the single photo detector generating an “ineterferogram”. The spectrum of the input light is directly generated by applying a Fourier Transform over the interferogram.
The “Neo” way for FT-IR
In NeoSpectra, all the optical and mechanical components are integrated on single MEMS chip, enabling FT-IR functionality on a chip scale. The monolithic integration is enbaled by using Si-Ware Systems’ proprietary Silicon integrated Micro Optical Systems Technology (SiMOST) platform.
|The conventional way||The Neospectra way|
|Core engine||Bulky Michelson interferometer with discrete optical, mechanical, and electrical components.||Single-chip Michelson interferometer with monolithic opto-electro-mechanical structure.|
|Optical alignment||Misalignment in interferometers’ components deteriorates performance.||Components are intrinsically aligned by lithography.|
|Measuring the position of the moving mirror||Additional interferometer with He-Ne Laser for position sensing||On-chip electrical sensing of capacitance between the motor driver and a fixed structure|