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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

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

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

FAQ #1 – Can I operate multiple laser diodes from the same power supply?

Here at RPMC Lasers, we have over 20 years of experience helping the photonics community with their solid-state laser needs.  Over this time, we have answered a wide range of questions from both end users and system integrators, ranging from application support to laser fundamentals.  Many of the questions we have received over the years have served to influence the topics you have read about on our blog, but for the first time, we are starting a monthly blog series dedicated to frequently asked questions (FAQs) e… Read More

Machine Vision For Inspection

Machine vision is defined as the substitution of the human visual senses and decision-making ability, by image acquisition and computer analysis to perform an inspection task.   This process is most commonly utilized as an active imaging technology to automate inspection and analysis for process control and robot guidance in industrial applications.  As automation has become more and more prevalent in the manufacturing sector, machine vision technology has rapidly grown into one of the largest markets for laser diodes around th… Read More

Laser Diode Fundamentals – Fiber Coupling 2

In the last blog post of our laser diode fundamentals series, we discussed the basics of fiber optics concentrating on two key parameters; core diameter and numerical aperture. In this blog post, we are going to turn the discussion to fiber coupling techniques conventionally used in laser diode packaging including butt coupling, ball lens coupling, and intermediate co… Read More

Laser Diode Bar Stress

In this application note, we plan to combine these two topics and look at one of the key factors that affects laser diode bar lifetime – stress and strains.  Despite the extreme power output of laser diode bars and stacks, which can exceed 2 kilowatts of power in quasi continuous wave (QCW) operation, the facet coating technology has improved to the point where it can handle intensities well over 20MW/cm2 making catastrophic optical damage (COD) no longer a limiti… Read More

Laser Diode Fundamentals: Single Longitudinal Mode Diodes

In the last installment of our Laser Diode Fundamentals series, we took a deep dive into the underlying physical properties behind the longitudinal mode structure of laser diodes.  In that blog post, we explained the advantages and disadvantages to both multi-longitudinal mode and single longitudinal mode diode lasers.  We are going to expand on what we learned about single longitudinal mode diodes lasers and take a look at a wide range of stabilization techniques which are used to ensure that a laser maintains single mode performance during its … Read More

Using Lasers to Detect Greenhouse Gasses

Being produced in nature through the anaerobic decomposition of organic matter trapped beneath the sedimentary layers of the earth, it is found abundantly near other fossil fuels such as in coal mines.  Even though it is the simplest of all the hydrocarbons, methane gas is used widely in industrial applications such as power generation, transportation, and industrial chemical manufacturing, in addition to its more commonly known use as a consumer fuel source…. Read More

Diodes for Optical Tweezers

Micromanipulation of sub-millimeter objects is one of the more underappreciated technical challenges in modern scientific research.   To fully understand their properties, objects such as dielectric spheres, viruses, bacteria, living cells, organelles, small metal particles, and even strands of DNA all require precise positioning under a microscope even though they can often only be tens of nanometers in size.  Since these objects are too small to manipulate with a pair of tweezers, a non-contact method needs to be used to trap and then manipulate these … Read More

Diodes for 3D Printing

Additive manufacturing, or as its more commonly referred – 3D printing, has revolutionized manufacturing processes over the past ten years.  This technology which was once reserved for high-end research and prototyping applications is now so commonplace that many elementary and middle schools through the US are utilizing them as part of their STEM curriculums. Regardless of cost or complexity, all additive manufacturing processes consist of four primary stages: 3D modeling, digital data processing, 3D object construction, and post-p… Read More

Digital Holographic Microscopy

Holography is simultaneously one of the most well-known and yet most misunderstood optical techniques.  The word hologram derives from the combination of two different Greek words “holo” meaning “whole” and “gram” meaning “drawing.”  Understanding the origin of the word itself helps to illustrate that a hologram is not just simply a three-dimensional photograph, but instead, it is a recording of “the whole” wavefront reflected or transmitted by an object including both its amplitude … Read More

Optical Particle Counting

Optical particle counting is widely deployed in cleanrooms around the world as a means for counting and sizing the number of particles in the air.  Most people who have ever worked in a clean room, are familiar with the Federal Standard 209E cleanroom classifications, such as class 10,000, class 1,000, or class 100, with the lower the number corresponding to the cleaner the room.  Where many people have misconceptions is that the classifications are not solely determined by the number of particles in the air but also t… Read More

Diodes for Acne Treatment

According to the American Association of Dermatology (AAD), acne is the most common skin condition in the United States, affecting up to 50 million Americans annually with a nontrivial percentage suffering from a chronic form of the condition. Fortunately, for people suffering from persi… Read More

Laser Diode Fundamentals: Understanding Longitudinal Modes

There are two critical parameters that all lasers diodes must meet to begin the lasing process.  The first one of these parameters is that there must be more gain than loss inside the laser cavity, the point at which this condition is satisfied is known as the gain threshold and was covered in the last installment in our Laser Diode Fundamentals series.   The second condition that must be met, is that there must be a longitudinal mode present inside the optical cavity which coincides with the laser’s g… Read More

Understanding Laser Diode Lifetime

In October of 2017 RPMC Lasers, published a white paper titled “How to Improve Laser Diode Lifetime! Advice and Precautions on Mounting,” where we went on to describe in great detail the various package types and the best practices for ensuring the laser diode are appropriately heat sunk. In light of extreme interest in this topic, we have decided to expand on this topic with this application note by discussing how electrical, electro-mechanical, environmental, and optical properties also affect the diode … Read More

QCW Laser Diode Stacks: The Perfect Solution For Hair Removal Systems

According to Grand View Research, laser hair removal is one of the most popular medical laser applications worldwide and is projected to reach 2.8 billion dollars annually by 2028. Laser hair removal became popular so quickly that by 2005 Alexandrite (the laser of choice at the time) was the second most popular laser crystal grown worldwide, even though there were no other mainstream applications for Alexandrite laser technology. As of 2020, laser diodes held the lion’s share of the market (over 39%), due to their high precision, efficiency, small footprint, and relatively… Read More

The Influence of Laser Wavelength on Raman Spectroscopy

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