Additional Resources
Blogs:
- “Multimode vs Single-Mode Lasers for Raman Spectroscopy“
- “What is Single Longitudinal Mode?“
- “Laser Diode Fundamentals: Beam Properties“
- “Why Should Single-Mode Fibers Have an Angle Polished?“
Whitepapers:
A single-mode laser is a laser that emits light in a single, well-defined mode or pattern. This mode can either be a single spatial mode, meaning the light is emitted in a single, narrow beam with a well-defined transverse intensity profile, or a single longitudinal mode, meaning the light is emitted at a single, well-defined frequency with minimal spectral spreading. Due to their high spectral purity and stability, single-mode lasers are used in various applications, such as telecommunications, spectroscopy, and precision metrology.
The term “single mode” is sometimes misused and misunderstood within the laser community. It refers to the number of modes in the laser beam along two axes: the transverse electromagnetic (TEM) plane and the longitudinal axis. The TEM modes determine the spatial distribution of the laser’s intensity, while the longitudinal modes determine the spectral properties of the laser, including the frequency content and linewidth. A laser is considered single-mode if it has only one mode along either the TEM or longitudinal axis or both. Single longitudinal mode lasers are ideal for applications where a narrow linewidth and precise wavelength are required and are commonly referred to as single-frequency lasers. However, they still have a defined linewidth.
Laser diodes, for example, are categorized as single-mode or multimode based on the far-field distribution in the lateral direction (slow axis). A single-mode laser has a bell-shaped distribution with one peak, while a multimode laser has a distribution with multiple peaks. Single-mode lasers typically have lower power but higher brightness. The output beam quality of a laser, as determined by M2, can be used to determine whether it is single-mode or multimode. A pure single-mode laser has M2 less than 1.3, a quasi-single-mode laser has M2 between 1.3 and 2.0, and a multimode laser has M2 greater than 2.0.
Single-mode lasers have a better beam quality, including a smaller focus diameter, lower divergence, and higher power density, compared to multimode lasers. However, single-mode fiber lasers have limitations, including a thin fiber core with a low damage threshold and low output power, making them unsuitable for applications requiring high-energy light. Multimode lasers, on the other hand, have higher output power and a larger end area, but are less suitable for long-distance transmission due to their greater dispersion and energy loss.
The spatial mode structure of a diode laser is determined by the ridge width of the waveguide, similarly as the core of a fiber-optic cable. For single-mode laser diodes, the ridge width is determined by the wavelength of the laser but is typically between 3 to 10 microns wide. Such a narrow waveguide allows for single transverse electric (TE) and transverse magnetic (TM) modes to be supported resulting in a perfect TEM00 beam profile. The limited volume associated with having such a narrow active area results in far less power generation and much larger power densities at the facet, but it also results in a much lower capacitance allowing for quicker switching, therefore, making single-mode laser diodes far superior for high-speed applications. Single-mode laser diodes are available in both free space and fiber coupled packaging configurations.
Only looking for Single Longitudinal Mode or Narrow Linewidth Lasers? See our Narrow Linewidth Lasers page!
Here at RPMC Lasers, we offer a wide range of wavelengths from UV as low as 349 nm to LWIR up to 16 µm with single-mode outputs, including DFB, DBR, and VBG stabilized, single-frequency diodes, as well as VCSELs, QCLs, single-mode CW DPSS and CW Fiber lasers, gas lasers, and more. These single-mode lasers are the ideal for a diverse range of applications including fiber laser seeding, confocal fluorescence microscopy, gas sensing, and telecommunications, just to name a few.
The FL CW/CW Modulated Series offers a variety of standard and custom CW fiber laser options. Available in both OEM and Turnkey formats, our 1um, 1.5um and 2um fiber lasers are manufactured to Telcordia standards and can be modified to meet your applications requirements. With available powers up to 100W at 1um, 30W at 1.5um and 40W at 2um, our CW fiber lasers are suitable for a wide range of applications. Available options and configurations include narrow linewidth, single frequency outputs, C and L-band broadband sources, PM fiber options, power tunability and high-speed trig./mod. Customized configurations are available upon request.
The Matchbox series offers excellent performance and reliability in the “World’s Smallest” ultra-compact, all-in-one, integrated laser head. They can operate on a 5V power supply while maintaining low noise operation. The monolithic design of the Matchbox Series laser includes thermally stabilized optics in a hermetically sealed housing, ensuring reliable and maintenance-free operation. This series is available in wavelengths from 405 nm thru 1064nm, with options for collimated beam or fiber-coupled output, and single-mode and multimode version.
The Skylark series of ultrareliable, high performance, CW single-frequency lasers are available at a variety of wavelengths with high average powers, making them well suited for a variety of highly specialized scientific and industrial applications. BRaMMS Technology® enables superior performance, high output powers, and outstanding beam properties in an overall compact footprint. The Skylark series of lasers are utilized in a range of applications including holography, metrology, spectroscopy, and quantum technology.
The LGK series of HeNe laser modules boast an excellent TEM00 beam, robust mechanical design, a long service life of up to 30,000 hours, and are available in 543nm, 594nm, and 632.8nm wavelengths, with output powers up to 20mW. Choose between standard and customized models, with options for single or multimode, random or linear polarization, Brewster window tubes, and fiber coupling. Designed for long life, low noise, and high stability, with many customization options, these HeNe lasers are perfect for applications including spectroscopy, interferometry, holography, medical, and more!
The HL Series offers versatile and high-quality laser diode products in a variety of wavelengths and high-power options, ideal for direct imaging, industrial, and bio/medical applications. These reliable, efficient, and compact diodes come in TO-Can packages, making them perfect for OEM integration. Additionally, they operate with TE mode oscillation and are RoHS compliant, ensuring safe use. Choose the HL Series for quality, reliability, and performance in laser diodes.
The LaserBoxx Low Noise series of CW diode laser modules, with a variety of wavelengths from 375 to 785nm and output powers up to 350mW, offers highly customizable laser solutions for OEM and plug & play modules. With advanced features such as excellent beam quality, stability, and modulation capabilities, our lasers provide ultra-low noise and a wide range of options for SM, MM, and PM fiber coupling. Our dedicated control software, USB and RS232 interfaces, and external controller with power display make integration, operation, and remote diagnostics a breeze. Additionally, our rugged and compact design and wide variety of standard wavelengths ensure that our lasers can meet your specific needs.
The LaserBoxx-SLM series are single longitudinal mode (SLM) CW diode laser modules available in green, yellow, red, and NIR wavelengths, delivering ultra-narrow linewidths, with excellent temperature stability and low noise current. Embedded firmware locks the laser on the same mode at each startup. This customizable, compact, self-contained laser module is available in turn-key or OEM versions and utilizes a proprietary alignment-free, monolithic resonator, and comes standard with a graphic user interface with remote diagnostics via USB, RS232, or direct I/O interface. With modulation capabilities and adjustable power options, the SLM Series is versatile and adaptable to a wide range of applications.
The LGR series of HeNe laser replacement tubes provide unparalleled performance for a wide range of applications. have a robust mechanical design, excellent beam quality, and a long service life of up to 30,000 hours. Standard and customized models are available in a large variety in the red, green, and yellow spectral ranges with output powers up to 20 mW. Options for single–mode or multimode, random or linear polarization, and Brewster window tubes for educational and scientific purposes.
The LXCc series is a range of compact, highly customizable, and flexible all-in-one laser combiners that provide the widest variety of wavelength options, up to 7 different laser lines (up to 500 mW output power per line), direct modulation on every source, SLM capabilities, proven long-term stability, and many other advanced features. The turnkey or OEM versions allow a large choice of lasers from 375nm up to 1064nm. The extension module provides the ultimate level of flexibility with options for up to 4 optical fiber outputs, AOTF modulator, motorized ND filter, integrated fast switching output ports for FRAP, or adjustable split power for light-sheet microscopy.
The R series of wavelength stabilized single–mode and multimode laser diodes offer narrow linewidth output in wavelengths from 633nm thru 1064nm. This highly customizable series offers package options ranging from components as basic as a TO-56 or 14-pin BF packaged diodes, to OEM modules including electronics, to UL/CE and IEC certified turn-key systems. The R series is the perfect source for various markets, including chemical analysis, bio-medical, fiber laser, and scientific applications.
The RWLD series offers competitively priced laser diodes with high beam quality and a wide variety of products to support multiple applications. Available in a wide range of wavelengths, power levels, and packages. The RWLD wavelength options span from 405nm to 1650nm, with output powers in the range of 10 mW to 300 mW, packaged in a TO-18 package with photodiode. We also offer customized options, such as a customized wavelength, output power, or a special package to meet your specific needs.
The REP series includes high-performance, tunable, single-frequency (DFB-like) diode lasers and Fabry-Perot laser diodes in wavelengths from 1270nm thru 2350nm, designed to address challenges in Gas Sensing, LIDAR, Spectroscopy, and Telecom. The REP series includes high-power and narrow linewidth options, covering various product ranges at the most popular wavelengths, providing customizable units with multiple packaging options, including the Fiber coupled 14-pin butterfly, TO39 (w/TEC), and TO56.
For a complete module incorporating the fiber-coupled butterfly package with an integrated current driver and TEC controller, designed for ease of operation, it is the ideal platform for high stability gas detection or remote sensing. See the DX1 Series.
The RHAML series of diode laser modules deliver a uniform, stable output beam that crucual for machine vision applcations, especially in 3D vision systems. The compact, RHAML series is a reliable light source that incoroporates a fucusing lens that can be easily adjusted by the user. Additionally, the RHAML series is fully IP67 compliant, making it an ideal solution for use in harsh environmental conditions and production/industrial facilities.
The RML series of laser diode modules are available with single mode fiber outputs with a set wavelength from 405nm – 2500nm. The compact RML series is available with up to 80mW of output power in a package measuring 15mm in diameter and 40mm in length (without connector) . As an option these modules are offered with a potentiometer for power adjustment, external TTL modulation up to 1MHz and analog modulation up to 100kHz.
The RPK Series of multiple, single-emitter fiber-coupled diode lasers are available in wavelengths from 405nm thru 1550nm with up to 300W output power. Our specialized fiber-coupling techniques ensure high efficiency, stability, and superior beam quality, while rigorous inspections and burn-in procedures guarantee each product’s reliability, stability, and long lifetime. Highly customizable packages allow us to meet our customers’ specific needs, providing high-quality products at reasonable prices.
The RWLP series offers an affordable and versatile solution for your laser application needs with single-mode and multimode options and wavelengths from 405nm thru the IR region. With customizable options, our team can work with you to solve any challenges you may face. Rigorously tested for long-term reliability, the RWLP series ensures consistent performance and high beam quality. Perfect for integration, this series supports multiple applications including biological and analytical instrumentation.
The TG Series of laser diodes emit in the blue spectral range with non-standard wavelengths from 420nm up to 460 nm, perfect for Life Science applications, with a typical output power of 50mW and an absolute maximum output power of 100mW. Assembled in a 5.6 mm (TO-56) packages the TG series is a suitable for a wide range of OEM applications that require blue/violet light.
The RWLS series of RGB White Laser Diodes offers customizable, versatile, and reliable solution for your laser applications. Available in a wide range of power levels, with three base wavelengths: 635 nm (Red), 520nm (Green), and 445nm (Blue), the RWLS series can be tailored to your exact specifications. Typically packaged in a pigtailed HHL configuration, with built-in TEC, there are also plenty of customization options including wavelength, power, and packaging.
The uniMir Series is a long-wavelength, single-frequency, DFB, CW Quantum Cascade Laser based on proprietary technology. The technology’s versatility allows them to address any wavelength between 10 and 18µm in CW and up to 21µm in pulsed mode. now commercially available in a sealed High Heat Load (HHL) package, with integrated collimating lens, thermistor, and thermoelectric cooler (TEC), well suited for integration into systems, or as a stand-alone turnkey system for R&D and detection applications.