There’s a famous phrase in the spectroscopy world, “fit for purpose.” This is a perfect mantra for selecting components. Selecting the right light source starts with the desired application. What are you trying to achieve with this instrument? What is the proper wavelength and power output? What market is it serving? What is the target final cost? The answers to those questions along with the explanations below should lead to an answer.
LEDs boast reliable lifetimes as well as low power consumption. They also come at a relatively low cost compared to other MIR light sources. The main tradeoff lies with power output, so these units are not intended for analytical accuracy. Portable gas monitors would be a great example application for these components.
Quantum cascade lasers (QCLs) are the gold standard for generating light anywhere between 4-10 microns. Our DFB (distributed feedback) models provide industry-leading linewidth resolution, enabling possible ppb measurements. QCLs also have reliable lifetimes while providing high power output. All this performance comes at a much higher cost, and power requirements for lasing start at around 500mA. An instrument using a QCL will be cost intensive and require quite a bit of expertise to pull off, but nothing will touch the sensitivity it can achieve.
Xenon (Xe) flash lamps
For wide spectral output and high frequency operation, look no further than the Xe flash lamp. With output ranging from 0.2 microns to 5+ microns, these lamps make it possible to create an instrument that detects multiple gases. However, these lamps should not be considered for measuring very low concentrations due to the wide output and stability. Although Xe flash lamps with emission out to 7 microns have been developed, the relative output past 5 microns remains low. Measurements further into the fingerprint region would be very difficult to achieve.
D* is known as the “detectivity” of a detector, or the photosensitivity per unit active area in a detector. As seen in the equation below, the lower the noise equivalent power (NEP) of a detector, the higher the D* (and vice versa). NEP is the minimum power of signal needed for a detector to overcome its noise floor, or for SNR to equal 1. The lower this value, the higher the sensitivity of a detector. This relationship shows, therefore, that the higher the D*, the higher the sensitivity as well. We can also see from the equation below that the smaller the detector active area (A), the higher the D*.
D* takes into account more than just a detector’s active area, however. It is also a function of the temperature [K] or wavelength [µm] of a radiant source, the chopping frequency [Hz], and the bandwidth [Hz] of a detector—as seen in the expression of detectivity as “D* (A, B, C),” with each letter corresponding to the three characteristics mentioned.
What makes D* so useful is that it allows a comparison of different active area sizes and chemistries. While D* provides a better gauge of sensitivity, detector characteristics such as light wavelength, response time, active area shape, and number of elements, as well as the necessary electronics, should be taken into account when selecting an infrared detector.
When the applications demand more sensitivity, cooling serves the function of lowering the noise floor of a detector without reducing its quantum efficiency (QE). As a result, the lower the temperature, the higher the D* at a certain input power. It’s important to remember that cooling drives up cost and complexity, so it’s best to consider uncooled detectors first. Hamamatsu offers a wide range of uncooled detectors as well as detectors with multi-stage thermoelectric (TEC) cooling and liquid nitrogen cooling.
Photovoltaic operation typically leads to slower measurements. Hamamatsu’s InAsSb detectors mitigate that situation by boasting a rise time on the order of nanoseconds. In addition, many infrared detectors contain materials that are not RoHS compliant (mercury and lead), but InAsSb material is fully RoHS compliant. In uncooled applications, InAsSb is a strong contender for providing big cost advantages as well.
Whether she has a camera in hand, or is working alongside her University Support Group team to solve a problem, Stephanie Butron tries to see things from a different perspective—like seeing the invisible side of mid-infrared. As an Applications Engineer at Hamamatsu Corporation, she enjoys learning more about the variety of projects and applications Hamamatsu’s customers are working on, and understanding better how Hamamatsu can help. When she isn’t helping people focus in on their research, Stephanie enjoys focusing her camera lens on the sights around her. From still lives to portraits, Stephanie tries to find new ways to look at the world.
It looks like you're in the . If this is not your location, please select the correct region and country below.
You're headed to Hamamatsu Photonics website for US (English). If you want to view an other country's site, the optimized information will be provided by selecting options below.
For modern websites to work according to visitor’s expectations, they need to collect certain basic information about visitors. To do this, a site will create small text files which are placed on visitor’s devices (computer or mobile) - these files are known as cookies when you access a website. Cookies are used in order to make websites function and work efficiently. Cookies are uniquely assigned to each visitor and can only be read by a web server in the domain that issued the cookie to the visitor. Cookies cannot be used to run programs or deliver viruses to a visitor’s device.
Cookies do various jobs which make the visitor’s experience of the internet much smoother and more interactive. For instance, cookies are used to remember the visitor’s preferences on sites they visit often, to remember language preference and to help navigate between pages more efficiently. Much, though not all, of the data collected is anonymous, though some of it is designed to detect browsing patterns and approximate geographical location to improve the visitor experience.
Certain type of cookies may require the data subject’s consent before storing them on the computer.
This website uses two types of cookies:
There are two ways to manage cookie preferences.
If you wish to restrict or block web browser cookies which are set on your device then you can do this through your browser settings; the Help function within your browser should tell you how. Alternatively, you may wish to visit www.aboutcookies.org, which contains comprehensive information on how to do this on a wide variety of desktop browsers.
Occasionally, we may use internet tags (also known as action tags, single-pixel GIFs, clear GIFs, invisible GIFs and 1-by-1 GIFs) at this site and may deploy these tags/cookies through a third-party advertising partner or a web analytical service partner which may be located and store the respective information (including your IP-address) in a foreign country. These tags/cookies are placed on both online advertisements that bring users to this site and on different pages of this site. We use this technology to measure the visitors' responses to our sites and the effectiveness of our advertising campaigns (including how many times a page is opened and which information is consulted) as well as to evaluate your use of this website. The third-party partner or the web analytical service partner may be able to collect data about visitors to our and other sites because of these internet tags/cookies, may compose reports regarding the website’s activity for us and may provide further services which are related to the use of the website and the internet. They may provide such information to other parties if there is a legal requirement that they do so, or if they hire the other parties to process information on their behalf.
If you would like more information about web tags and cookies associated with on-line advertising or to opt-out of third-party collection of this information, please visit the Network Advertising Initiative website http://www.networkadvertising.org.
We use third-party cookies (such as Google Analytics) to track visitors on our website, to get reports about how visitors use the website and to inform, optimize and serve ads based on someone's past visits to our website.
You may opt-out of Google Analytics cookies by the websites provided by Google:
We inform you that in such case you will not be able to wholly use all functions of our website.