Infrared detectors

– application examples from industry and business

Gas analysis

The unique functionality of VIGO products is highly appreciated mainly on the volatile substance analyzers market. The detectors are used for monitoring process gases in chemical, refining, power generation, food and aerosol production industries. Photodiodes and photoresistors operate as a part of ultra-sensitive optoelectronic analytical devices in which the source of radiation are medium- and long-wave quantum cascade lasers (QCLs). Devices incorporating VIGO detectors are used as electronic “noses” – they can measure very small concentrations (ppb and ppt) of chemical substances in a mixture. Apart from process gases analysis, such systems are excellent for analyzing undesired vapors, such as pollutants and hazardous or flammable compounds, and for quality control – finding escapes and leakages. An invaluable advantage of optical detection modules is their insensitivity to electromagnetic interference. Such devices can be left in hazardous areas, and measurements can be taken from a safe place.

Laser power control and calibration

Powerful laser sources, mainly high-power CO2 and solid-state lasers, have for many years been used on quick and precise hard material treatment, large format cutting, engraving, cleaning and welding markets. Such sources operate within the mid infrared range, as high absorptivity of that type of radiation enables contact-free modification of materials by means of heating. A natural consequence of that situation is a demand for sensors operating within the same range of spectrum as lasers do, and enabling control of beam power and position. VIGO System offers a wide range of durable IR detectors optimized for the wavelengths of 2 to 16 µm. Fabrficated structures are characterized by small heat capacity and insignificant impact of thermal signal on optical signal. Depending on the customer’s requirements, various active area sizes are available. The VIGO research team prepares also multi-component linear or quadrant detectors, ideal for radiation source positioning.

 

Real-time water quality control

Access to clean, drinking water still remains a luxury for many inhabitants of Earth. Even in areas where plenty of H2O is available, there is a problem with analyzing the substance before it is consumed. Additionally, the risk of deliberate poisoning of reservoirs by groups of terrorists is growing, which in combination with slow operation of the conventional instruments for liquid analysis may result in a failure to detect the danger quickly enough. The present situation is to change thanks to the WaterSpy project, co-run by VIGO System. Under the project carried out by 9 entities from Europe, a technology for photonic analysis of liquids is being developed. The device being built, which will be both accurate and handy, will consist of fiber-coupled QCLs and detectors supplied by VIGO System. Thanks to the use of ATR spectroscopy, a very good signal-to-noise ratio is to be obtained, and the method will not require pre-cleaning samples before measurement. Taking into account the present progress in works, we can say that the VIGO System detectors will soon guarantee supply of clean and refreshing water to citizens.

 

Medical applications

There are great hopes that the VIGO System detectors will perform well in medical applications. It is sufficient to say that the Polish sensors enable absolutely non-invasive blood analysis. Successful attempts at measuring oxygen saturation, blood flow, and even glucose content have been documented, with an error rate comparable to that shown by traditional glucose meters. All that has been achieved with the use of infrared detectors, by means of analyzing the spectrum of laser radiation reflected from parts of human body supplied with large amounts of blood.

There are also commercially available devices on the market that utilize technologies developed by VIGO System. Those are apparatuses for exhaled air analysis. They enable determining tumor marker levels, or diagnosing asthma or liver diseases. Such devices can be used also for monitoring the composition of air in operating rooms. In addition, the detectors supplied by VIGO System are used for controlling the power and positioning of laser beams used by surgeons, dentists or dermatologists.

Analysis of temperature distribution in fast moving objects

The unbeatable speed and sensitivity of VIGO System detectors make them useful in applications where the response time is a matter of safety of hundreds of people, and possible failures and delays may result in losing enormous amounts of money. One of the main applications of PV photodiodes, which are the hearts of detection modules, is measuring the temperature of train sets. There are various types of heat sensors available on the market, but the unique VIGO System products excel the other devices based on pyroelectric bodies, bolometers and thermocouples in terms of response time, limit of detection, and resistance to external conditions. Detectors incorporated in devices installed between the rails enable contactless, real-time measurement of the temperature of wheels, brakes, shock absorbers and chassis of train sets. Information on possible overheating is immediately sent to competent units. The detectors are used also for scanning all the rolling stock before a train enters a tunnel. Thanks to the undisputable advantages of VIGO System products, they have been chosen for protecting train passengers all over Europe.

Engine emissions’ monitoring and control

Increasingly strict standards concerning the presence of carbon dioxide, nitrogen oxides and dusts in car exhaust gases force the vehicle manufacturers to use precise and reliable gas analyzers. That creates demand for spectroscopes that guarantee top accuracy. To respond to the demand from the market, VIGO System offers HgCdTe detectors which are perfect for spectrum analysis and show sensitivity within a broad wavelength range from 2 to 16 µm. They enable detection of all fuel combustion products, as the absorption lines of the substances searched for fall within the range of the wavelengths detected by the devices. That is how concentrations of CO2, CO, NOX and hydrocarbons can be monitored. Thanks to the excellent sensitivity, resolutions at the level of a single ppm or even ppt can be obtained, which means ultra-accurate estimation of trace amount of a substance. It is worth stressing that the detection limits of VIGO devices are at the top world levels, and reach the fundamental BLIP limits.