What is a spectrometer?

A spectrometer is a device used to analyze the spectral composition of light. It works by dispersing white light from a light source through a prism or diffraction grating into a series of discrete wavelengths, also known as a chromatic spectrum. The resulting spectrum is subsequently detected by a photodetector, which converts its intensity profile into electrical signals, allowing further analysis to be performed in the digital domain.
A transparent container with sample material is placed in front of the light source. A beam of light is transmitted through the container into the spectrometer. Parts of the incident light spectrum are reflected off, absorbed by, or transmitted through the sample. The way the incident light interacts with the sample is different for each sample material. By analyzing the resulting spectral content, it is possible to determine the chemical composition of the sample. This makes spectrometers particularly useful in chemistry, physics, biochemistry, and other similar applications based on the spectrum analysis.

The optical bench

The inner chamber of the spectrometer contains a set of optical components forming an optical bench. A beam of light is guided into the optical bench through a very narrow entrance slit. The slit is typically located behind the SMA optic fiber port of the spectrometer, and it is used to control the light entering the optical bench. Subsequently, light hits several very precisely manufactured and positioned optical components, until it finally reaches the photodetector in the form of a chromatic spectrum.
There are several different optical bench configurations, each with its advantages for a specific use case. One of the most commonly used optical bench configurations is the “Czerny-Turner” configuration. It offers outstanding overall performance in a relatively small space. Below is a simplified diagram of a typical Czerny-Turner configuration, containing a set of optical components such as diffraction grating, collimating, and focusing mirrors, arranged in the form of the “W” letter (Figure 1).

Figure 1) Block diagram of a typical “Czerny-Turner” spectrometer setup

Broadcom Q-series spectrometers offer solutions for the broadest range of applications

Broadcom’s Qmini and Qwave series of compact spectrometers combine state-of-the-art optical and electronic components to achieve very high performance in a small form factor. The Q-series spectrometers are based on the Czerny-Turner configuration. This configuration does not use moving parts, avoiding any possibility of optical misalignment. This ensures reliable and stable long term performance.
The Q-Series offers spectroscopy for measurements of ultraviolet (UV), visible (VIS), and near-infrared (NIR) light, covering ranges between 190 nm and 1100 nm. All Q-series spectrometers have excellent thermal stability and are factory-calibrated after production.
Due to their unique set of advantages, Broadcom Q-series spectrometers are perfectly suitable for integrating into high-volume applications, and for various real-life applications such as process control and monitoring, biomedical applications, chemical research, environmental analysis, medical and pharma applications, forensic analysis, Raman spectroscopy, and many more.

The Qmini series – miniature yet powerful spectrometers for portable analysis

This product is developed with mobility in mind: due to its compact size of only 64 x 42 × 14.5 mm it can be easily integrated into space-constrained applications, making it a perfect solution for mobile analysis. Onboard processing capabilities save the processing cycles of the host controller, making it possible to use them in IoT setups or similar MCU or MPU-driven applications. Despite its size, it delivers a variety of functionalities and connectivity options, common to all Q-series spectrometers.

The Qmini series consists of differently designed spectrometer configurations covering a wide spectral range starting at 220 nm up to 1100 nm.

Part Number Product Configuration Wavelength Range Optical Resolution
AFBR-S20M2UV Qmini UV 220 nm to 400 nm 0.5 nm
AFBR-S20M2VI Qmini VIS 370 nm to 750 nm 0.7 nm
AFBR-S20M2NI Qmini NIR 730 nm to 1080 nm 0.7 nm
AFBR-S20M2WU Qmini Wide UV Sensitivity optimized at 300 nm 225 nm to 1000 nm 1.5 nm
AFBR-S20M2WV Qmini Wide VIS Sensitivity optimized at 500 nm 225 nm to 1000 nm 1.5 nm
AFBR-S20M2VN Qmini VIS/NIR 480 nm to 1100 nm 1.5 nm

More detailed information on Qmini series spectrometers can be found in the Qmini Product Brief document at this LINK

The Qmini spectrometer

The Qwave Series – compact spectrometers that offer performance typically found in much bulkier designs.

Armed with a high-resolution 3648-pixel linear CCD detector, featuring optimal resolution down to 0.2 nm, focal length of 75 mm, high dynamic range of up to 1500:1, and spectral coverage ranging from 220 to 1030 nm, the Qwave series can cope with much more demanding setups, still maintaining a relatively small size of 89.5 × 68 × 19.5 mm. The Qwave series is intended for more critical spectral analysis, where the high resolution and throughput of the spectrometer is required.
More detailed information on Qwave series spectrometers can be found in the Qwave Product Brief document at this LINK

The Qwave spectrometer
Part Number Product Configuration Wavelength Range Spectral Resolution
AFBR-S20W1UV Qwave UV 220 nm to 390 nm 0.2 nm
AFBR-S20W1VI Qwave VIS 350 nm to 880 nm 0.5 nm
AFBR-S20W1NI Qwave NIR 700 nm to 1030 nm 0.4 nm

Broadcom Q-series spectrometers are supported by a very smart and intuitive spectroscopy software called Waves

All Broadcom Q-series spectrometers are supported by the Waves software, developed for general-purpose spectroscopy applications. By featuring a clean and intuitive interface, the Waves software greatly simplifies data acquisition and spectrum evaluation. The software uses advanced algorithms for enhanced data acquisition and analysis, offering a set of useful options: from capturing and displaying a series of spectra, to performing sophisticated transmission, absorption, and reflection measurements. Besides, Waves software enables importing most of the ASCII-based file formats, as well as exporting measurement data as ASCII tables, compatible with most numerical analysis software solutions available on the market. The Waves software is very intuitive, and most operations can be completed with just a few mouse clicks.

The Waves evaluation software

SDK for the .NET framework

Custom Spectrometer applications can be quickly developed, thanks to excellent software support. Broadcom provides the Software Development Kit (SDK) with .DLL libraries for the .NET framework, along with documentation and examples. These libraries enable the rapid development of custom applications, using many programming languages that support the .NET framework: C#, Visual Basic .NET, C++, Delphi, LabVIEW, MATLAB, and Mathematica.
Furthermore, a powerful yet simple communication protocol enables the spectrometer to be controlled directly by a microcontroller or microprocessor (MCU or MPU). This enables spectrometer control and analysis of spectrum measurement data across various embedded systems and IoT applications. It also simplifies integration into larger analyzing systems.
Broadcom Q-series spectrometers include a wide range of connectivity options, including USB, UART, and SPI. A set of digital I/O ports that can be configured as trigger inputs, shutter or flashlight source control, process controls, or GPIO pins. An external power supply connector is also available if the USB host is not used, for example in an industrial system.

As a technical editor and writer, I am given an opportunity to bring technology closer to people. My updates are focused on the most recent solutions and applications from the global semiconductors industry.

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