Dr. Sidi Aboujja from SemiNex presents two technical talks on our latest SOA array and highly reliable Triple Junction for automotive LiDAR at SPIE DCS 2023. These talks capture the technological advancements and application insights so that LiDAR can achieve long range with low cost and small form factors. The abstracts of these talks are lis… Read More
Accurate OH measurements are a growing need in combustion research, but existing sensor architectures are challenging to make economic, compact, and robust. The need for robust OH sensors is amplified in the global effort to decarbonize combustion. Many species, such as CO and CO2, have robust, high-speed laser absorption sensors targeting their fundamental vibrational bands in the mid-infrared; however, certain species like OH do not have a favorable vibrational spectrum, complicating sensing in the mid… Read More
Combat zones can be extremely chaotic. With a massive influx of sensory input, implementing clear communication, rugged tools, and reliable instrumentation is key to a successful mission. One of the most challenging tasks in any aerial combat situation is determining which assets on the ground to target and which ones to avoid. Because of this challenge, a practice, commonly referred to as “painting the target,” was developed and has been successfully deployed for many years, allowing ground forces to identify and designate targets for successful engagement by aeria… Read More
Q-switching is the most effective method for producing high energy pulsed lasers. While there are many different varieties of a q-switch, they all follow the same basic operating principle. Q-switches temporarily increase the cavity losses so that the gain threshold is artificially high preventing the laser from emitting light. This process allows the population inversion inside of the gain medium to grow until it becomes fully sa… Read More
A significant and well-recognized difference between lasers and conventional, incoherent light sources, is the ability to concentrate laser emission in short pulses, with durations going down to a few femtoseconds, containing potentially only a few optical cycles. Technically, you can drive an incoherent LED source using current pulses. However, each pulse would have a maximum power (i.e. a peak power) equal to the average power of the same device if a continuous bias were applied. Only laser cavities can concentrate the stored energy within active materials in such a way to achieve peak powers orders of magnitude higher than their ave… Read More
In that blog post we cited NATO standard STANAG 3733, which required that the laser beam have a divergence small enough so that 90% of its energy is on target 95% of the time assuming a 2.3 x 2.3 m target. We went on to explain that most laser designators are designed to be used at distances up to 5 km. Therefore, one of the most critical factors when choosing a laser source is the beam d… Read More
Spectroscopy is a class of analysis methods meant for chemical species identification and concentration measurement, based on emission spectra detection, if irradiated by an adequate light source. Fluorescence-based spectroscopy is one of the oldest spectroscopic techniques. This technique utilizes electron-photon interactions and relies on the absorption of high-energy photons and the subsequent emission of lower-energy, longer-wavelength fluorescence photons, with the energy difference associated with vibrationa… Read More
Nearly one-third of all Americans have at least one tattoo, and of those who do roughly one-quarter of them say they regret getting it. As a result, nearly 27 million people in the United States alone have at least one unwanted tattoo. Based on these numbers it is easy to see why the world-wide tattoo removal market exceeded 11.6 billion dollars in 2016. The vast majority of these procedures are done using laser-based tattoo removal treatments because they result in the least amount of sc… Read More
In actively Q-switched lasers, the user controls the pulsed laser output, so that no laser pulse emission occurs without providing a proper input signal, aka “the trigger”. Due to the trigger signal propagation through the interface electronics, the Q-switch driver chain, and the laser resonator build-up time, a time delay (Td) is present between the externally-supplied trigger signal and the actual laser pulse emitted by the laser source. The Td can show fluctuations if any electronics or optics involved in the pulse generation process have a functional varianc… Read More
Industrial laser induced breakdown spectroscopy typically involves the elemental analysis of various metals. In our previous application note titled “Laser Induced Breakdown Spectroscopy (LIBS) in Biomedical Applications,” we discussed the fundamentals of the technique, emphasizing the use of q-switched diode-pumped solid-state lasers as the excitation source. In this blog post, we are going to explore the possibility of utilizing nanosecond pulsed fiber lasers as the excitation source. We will also discuss the pros and cons of that approach, specifically for the characterization of metals and metal… Read More
The popularity of laser induced breakdown spectroscopy (LIBS) has been rapidly growing since its introduction in the 1960s, and is now used in industrial, military, scientific, and medical applications. Nowadays LIBS is rapidly becoming an indispensable tool for elemental analysis and is generally viewed as a complementary technique to other elemental methods such as mass spectrometry. Within the medical field, LIBS can be used for analyzing hard/calcified tissues, soft tissues, biomedical specimens; as well as disease detection and even during laser-guided surgery. In this application note, we will explore these uses of LIBS in the medical/biomedical application space, by taking a look at some of the common applications as well as both laser and system requirements. It is important to note that … Read More
Injection molding is a widely used process for rapidly mass-producing low cost highly uniform mechanical parts. On a cursory level, it is a relatively straight forward process by which molten material (metal, glass, polymer, etc.) is injected into a hollowed-out cavity, cooled down to solidify, and then ejected. This results in the material being permanently shaped to the internal cavity of the mold. This process has been around for hundreds if not thousands of years with the original molds being made out of clay and then broken apart to reveal the fini… Read More
Historically, Helium-Neon (HeNe) lasers were often the first choice for precision instrumentation, measurement setups and some spectroscopy applications. It was invented in 1960 and technologically it was one of the first lasers with extraordinary good parameters. The mechanical and optical design is quite simple (apart from sophisticated glasswork to make the tube itself) but the gas lasing medium and overall construction provide some intrinsic advantages. But also a number of disadv… Read More
Laser alignment can be a challenging task, but aligning a laser beam doesn’t have to be as complicated as it might seem with the right tools and proper techniques. Multiple tried-and-true methods have been developed over the years, utilized by technicians and engineers to simplify the alignment process. With the development of these methods, along with some tips and tricks, you don’t need to be a laser expert to perform your alignments with relative ease, ensuring your laser path is right where you want it to be and your beam is on target e… Read More
As discussed in previous posts, Raman spectroscopy is a rapidly growing analytical technique used in a wide variety of industries for material identification, but with so many different laser options it can be somewhat challenging to understand which laser is best for which application. To help elevate some of the confusion around this issue, we released an application note this past August titled “Multi-Mode vs. Single-Mode Lasers for Raman Spectr… Read More
Raman spectroscopy is one of the fastest growing and most diverse applications in all of laser spectroscopy. As a result, it can be rather challenging at times to sift through the wide-ranging laser options all being marketed for Raman spectroscopy. In this application note we will tackle one of the most common questions that arises when picking a laser for Raman spectroscopy; “Should I chose a single-spatial mode or multi-spatial mode laser for my application?” On the surface, this seems like a simple question since Raman is a nonlinear optical effect and therefore the tighter the beam can be focused the higher the conversion efficiency. Seemingly a single-mode laser would be preferable, but in practice there are other factors that can complicate … Read More
As discussed in a previous blog post, flow cytometry is an extremely valuable methodology employed by scientists around the world for analyzing individual cells via fluorescence tagging. By using several lasers throughout the visible spectrum, you can now excite a wide variety of fluorophores such as the ones shown in the figure below, increasing the number specific cell properties that you … Read More
iode lasers offer a vast range of wavelength options from the ultraviolet through the infrared. But, there is still one glaring hole in the visible spectrum between 520 nm and 633 nm. This region, which is often referred to as the “yellow gap,” results from the disparity between the upper range of InGaN diodes and the lower range in AlGaInP. When most people talk about Nd:YAG or Nd:YVO4 DPSS lasers, they are very familiar with the main 1064 nm laser line, and for a good reason, since it is the most efficient tra… Read More
Laser amplifiers are an invaluable tool because they allow for a laser’s power to be increased while maintaining its basic spectral properties. In principle laser amplifier noise is no different than the amplifier noise induced in an audio system, and just as in a home stereo system the quality of the amplifier will have a tremendous effect on the quality of output signal. Therefore, in this post we will attempt to answer the question what is laser amplifier noise, and perhaps more importantly how amplifier noise can affect the overall performance of yo… Read More
The first HeNe laser was developed in 1960 at Bell Labs by Ali Javan, in conjunction with William Bennet Jr. and Donald Herriott. A helium–neon (HeNe) laser, is a type of continuously operating, or continuous wave (CW) gas laser in which the gain medium is a 10:1 mixture of helium and neon, pressurized within a glass tube. When a DC current is applied to two electrodes on opposite ends of the tube, helium atoms are excited into metastab… Read More
Fluorescence imaging is a non-invasive imaging technique that utilizes the mechanism of fluorescence – matter emitting light of a particular wavelength after absorbing photons – which helps visualize biological processes taking place in a living organism. Tissues, cells, and their cellular structures are mostly water, making them transparent and difficult to view with traditiona… Read More
Mid-IR molecular spectroscopy is a rapidly developing and promising technique, enabling high-performance chemical detection and analysis for industrial or environmental purposes, with new wavelength ranges becoming commercially available. The essential component for such applications is the laser source, adapted to the specific spectral lines (the fingerprint) of the target molecule. Quantum Cascade Lasers (QCLs) are a perfectly suited solution to build such analysis… Read More
Laser diodes must meet two critical requirements to facilitate the lasing process. The first requires that, at a minimum, the laser cavity’s gain increases to the point that it reaches unity with the level of losses. This unity state is known as the gain threshold. The second requirement is that there must be a longitudinal mode present inside the optical cavity, coinciding with the laser’s gain curve. This article explores precisely what longitudinal modes are and how they affect the laser diode’s pe… Read More
For any laser to function, there must be more gain inside the laser cavity than loss, and the point at which the laser gain is just large enough to overcome the cavity loss enabling lasing is called gain threshold. While simple, in theory, this concept of gain threshold can be particularly challenging to understand, particularly when it comes to diode lasers. Therefore, as part of our ongoing blog series expanding on the topics covered in our Lasers 101 section, we are going to explore the concept of laser diode gain threshold in this … Read More
Once thought to be impossible, blue, green and UV laser diodes have now become commonplace. These lasers are being used in a wide range of applications from blue-ray players to commercial lighting & displays to copper welding. In this post, we are going to take a look at the underlying material properties of semiconductors, GaN in particular, and how it has led to the development of blue, green and UV las… Read More
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