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Why should single-mode fibers have an angle polished?

When you look through a window at night and see your reflection, that is because on average 4% of the incident light is reflected at the interface between air and glass.   While 4% may seem like a small amount when dealing with lasers, a 4% back reflection can have more than enough power to destabilize or even permanently destroy the laser.    If the laser beam is perfectly aligned through the system, so too will the back reflections be perfectly aligned to go back into the las… Read More

Why Shouldn’t You Voltage Drive a Laser Diode?

Electric power is determined by the product of the voltage and current supplied to a device. As a result, when designing an adjustable power supply, one of those two parameters must be variable, and the other constant if you want to be able to tune the power supply to your desired output. These two types of supplies are known broadly as constant current (CC) and constant voltage (CV) output circuits. When driving a laser diode, both CC and CV power supplies have pros and cons, but the rule of thumb is that you should always use a CC supply and never… Read More

Why are single-emitters winning over bars

Ever since the industrial fiber laser boom in the early 2000’s, there has been an ongoing debate about the most efficient way to produce high power, fiber-coupled, diode pump lasers. At its root, this debate comes down to the question of single-emitters versus diode bars. While single-emitters cannot come close to the power levels produced by diode bars, typically only producing a few watts of output power, they have several advantages over bars that make them far more desirable for systems in… Read More

How do DPSS lasers fill the ‘yellow gap’

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

Bright Solutions Offers the Wedge HF and XF Series Sub-ns Lasers

Thanks to the experience Bright Solutions has acquired in the state-of-the-art design of sub-ns DPSS lasers over the years, the Wedge family has recently been updated in terms of performance and available models. These improvements include increased average output power, and improved pulse energy stability, while maintaining a sub-ns pulse width and the ability to optimize laser performance at higher repetition rates. They also boast high peak output powers, with relatively low energy and heat generation, as well as myriad of customization possibilities and options to tweak and enhance yo… Read More

How to get the right laser spot at the right distance? – Part 2

In part one of this blog series, we set out to answer the question of “how to get the right laser spot at the right distance?”  As we went on to explain, this simple question doesn’t have a simple answer, especially when we are talking about single-mode fiber optics.  In that post, we took the time to go through
an introduction of Gaussian beam optics and provided a few examples of how that can be used to determine the lens you need to choose for a given spot size.  In part two, we are going to explore the far more straightforward case of imaging a multi-mode las… Read More

Requirements for Time Gated Active Night Vision Imaging Systems Blog

At RPMC, we are excited to announce the release of our newest white paper titled “Laser Requirements for Time Gated Active Night Vision Imaging Systems.”  In this paper, we review the fundamentals of modern night vision camera technology. We then go on to discuss the differences between active and passive imaging systems.  Finally, we will explore the advantages and disadvantages of using laser-based, active imaging systems and illuminating why, in some instances, lasers are the preferred illumination source, despite their inherent … Read More

RPMC Offers New Homogenized Diode Laser for Raman Spectroscopy

RPMC is proud to announce the release of their new Homogenized Multi-Mode 14-Pin BF Diode.  This multi-mode, wavelength stabilized laser features high output power with low power consumption and narrow spectral bandwidth. Another exciting feature is the shaped and homogenized beam profile, which evenly spreads out the power density and shapes the beam to match the field of view of a camera. The Homogenized Multi-Mode 14-Pin BF Diode is designed to replace expensive DFB, DBR, fiber, and external cavi… Read More

Why a larger beam results in a smaller spot size in laser designation?

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

Light-sheet Microscopy: Why are Two Beams Better Than One?

In the past, we have published several different blogs and whitepapers relating to both Raman and fluorescent confocal microscopy.  Therefore, there is no need for us to repeat the basics here, so we will simply point out that while traditional confocal microscopes provide excellent spatial resolution, they do so at the trade-off of producing extremely large intensities at the… Read More

What is Laser Amplifier Noise?

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

How to get the right laser spot at the right distance. – Part 1

Building upon our recent series of blog posts on fiber-coupled diode lasers, we now turn our attention to how you can manipulate the laser light coming out of a fiber.  Perhaps the most common question we get here at RPMC, is how to get a specific laser spot size at a given distance.  This seemingly simple question of “which lens should I use?” or “how to get the right laser spot at the right distance?” is actually a rather complex problem that is highly dependent on the particular type of fi… Read More

Analog vs. digital modulation – Which is better for you?

For people without a background in electrical engineering, understanding the finer details of analog and digital modulation can be quite challenging.  This is compounded by the fact that most texts on the subject already assume that the reader has a working knowledge of linear systems and Fourier analysis, which can be a significant obstacle for most. Therefore, it is no wonder that one of the most frequently asked questions we get here at RPMC, is “should I use analog or digital modu… Read More

Pros & Cons of Pigtailed Laser Diodes vs. Detachable Fiber Coupled

Approximately half of the laser diodes that we provide here at RPMC Lasers are fiber-coupled.  For this reason, we have decided to build upon our recent two-part blog on fiber coupling in our Laser Diode Fundamentals series by exploring the differences between pigtailed laser diodes and fiber-coupled laser diodes.  To understand the differences, first, it is helpful for us to review core diameter, which is an important principle discussed in the first part of our fiber coupling series. When thinking about a fiber’s core, it is useful to separate them into two different categories single-mode and … Read More

How Removing the TEC Increases Laser Diode Stability

As most people already understand, a laser diodes performance is highly dependent on its operating temperature, which is why most mid- to high-end laser packages utilize embedded thermoelectric coolers (TECs).  The strong temperature dependence arises from two fundamental properties of the diode itself.  First, as the temperature of the semiconductor varies, it’s gain band shifts up or down, this is known as redshifting and blu… Read More

3 important things when choosing a laser combiner for Flow Cytometry

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

Automotive LIDAR

Over the past year, we here at RPMC Lasers have published several different pieces of technical content on various LIDAR applications.  Some of our more recent posts include a white paper titled “Single Frequency Fiber Lasers for Doppler LIDAR,” and a blog post on the use of aerial LIDAR in bathymetry.  LIDAR is quickly becoming one of the most rapidly growing sectors of the overall laser market.  In fact, Market Insider recently reported that “ The market for LIDAR is expected to grow double in size in the next five… Read More

Laser Diode Fundamentals: Bandgap Energy and Wavelength

Diode lasers are unique amongst most other laser sources for their extensive range of available wavelengths.   The breadth of output wavelengths has allowed diodes to become one of the most versatile laser sources, with wavelengths available from ultraviolet to the infrared.  To understand why semiconductor diodes have such a wide range of wavelength options, we must first take a look at the underlying physical principles behind energy levels and stimulated… Read More

Arroyo Releases New TEC Controller for OEM Applications

Arroyo Instruments is proud to announce the release of the new 586 Series TECPak.  The 586 TECPak offers up to 392W of output power and its display-less operation is a combination of its smaller brother (the 585 TECPak) plus the high-power output of the 5400 TECSource. Arroyo Instruments designs and manufactures highly accurate laser diode drivers, temperature controllers, and fixtures for test and measurement of laser diodes… Read More

The Three Leading Aesthetics Applications

RPMC Lasers has made this blog post to show the top three aesthetic laser applications our customers have worked on. Our team of laser experts have over 100 years of combined experience working with our customers, and during that time, we have helped countless engineers and designers by combining our understanding of lasers with their knowledge of the applications to find the perfect laser solution.  This close partnership between suppliers and end-users allows us to provide informed consultation about both laser specifications and their app… Read More

LIDAR Becoming the Future of Bathymetry

Bathymetry is the study of the underwater depth in oceans, lakes, or seas and is used to generate detailed topographical maps of bodies of water around the world.  While there are several different methods of underwater mapping including sonar, in recent years LIDAR-based bathymetry techniques has become more and more popular.   One of the primary advantages of LIDAR is that it can be performed by a laser mounted on aircraft or drones, enabling aerial surveillance of shallow waters and coastal regions where larger watercraft are not able… Read More

Introduction Multi-photon Microscopy

Fluorescence microscopy is deployed widely in biological sciences for identifying the spatial distribution of molecules of interest in complex heterogeneous samples, including living cells.  Over the past 100 years, this method has been heavily dependent on the use of fluorescent tags which have uniquely engineered excitation and absorption spectra, and are functionalized to bond with particular molecules of interest.  Not only do these tags increase the technique’s specificity, but they also reduce photochemical degradation of the sample by moving from ultra-violet to visible excitation wa… Read More

Specifications for Target Imaging

Last year we published a blog post on the subject of combining active imaging and night vision by using time-of-flight (TOF) gated lidar to produce three-dimensional images of a target without the need for visible light.  We will revisit this topic, but instead, focus our attention on the importance of the laser specifications itself as opposed to the underlying principles of the me… Read More

How Can RPMC Provide the Right Custom Laser Solution?

For over 30 years, the laser diode experts at RPMC Lasers have facilitated successful collaborations between customers and suppliers. Our team prides itself on the knowledge and experience acquired in the industry and our dedication to providing system integrators with customized laser packaging solutions. Over the years, we have worked in conjunction with many engineers and designers to develop novel laser diode solutions, helping to ensure the success of their… Read More

Laser Diode Fundamentals: Diode Gain Threshold

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