The RBAT and REA series diode-pumped solid-state (DPSS) gain modules from Cutting Edge Optronics serve as central building blocks for high energy, high repetition rate burst-mode laser systems. Burst-mode laser systems achieve high pulse energy in combination with high repetition rate operation by grouping a series of closely spaced pulses into short bursts, thereby reducing the overall average system power. Diode pumping enables burst durations on the order of 100 ms, in contrast to flashlamp-pumped systems, which are limited to about 10 ms bursts. Repetition rates within the burst can be tunable from a single pulse to 1MHz with flexible pulse durations. A sequence of RBAT and REA modules with rod sizes ranging from 2 mm to 32 mm, along with Cutting Edge Optronics’ eDrive laser diode drive electronics, are key components in producing bursts with better than 1% burst-to-burst stability and better than 2% pulse-to-pulse stability within the burst. A long pulse burst-mode laser system provides an alternative to continuously pulsed and CW lasers in applications such as flow diagnostics and other scientific research. 

RBAT Modules – Compact, Flexible Gain Modules

• The RBAT series offers rod diameters from 2 mm to 4.5 mm, using standard gain media such as Nd:YAG or Nd:YLF.
• These modules can operate under continuous wave (CW) or quasi-continuous wave (QCW) pumping.
• In practical systems, RBAT modules support CW output powers up to approximately 150 W and long-pulse energies around 500 mJ.
• Because of their small size and flexibility, RBAT modules are suitable as the master oscillator or initial amplifier stage in diode-pumped MOPA (master-oscillator power amplification) systems, especially those intended for pulsed, burst-mode or Q-switched operation. 

REA Modules – High Energy, High-Capacity Amplifiers

• The REA series supports larger rod diameters (from 4 mm up to 32 mm), allowing much higher stored energy, which is a critical factor for achieving high output energies.
• Under CW operation, REA modules can deliver output powers up to approximately 650 W.
• For pulsed or burst-mode operation, they can provide high pulse energies – making them well-suited for amplifying seed pulses from oscillators to the energy levels required for demanding applications in both single-pass or multi-pass configurations.
• REA modules can be configured as QCW diode-pumped amplifiers in nanosecond MOPA laser systems or used in unstable resonator designs for high peak energy and high average power applications. 

Why Cutting Edges Optronics’ RBAT + REA Architecture Works Well for Burst-Mode / QCW Lasers

• Operating amplifiers in quasi-CW (QCW) or burst-pumped regimes allows the modules to handle high pump powers intermittently, avoiding the thermal loading and gain medium stress that continuous high-power pumping can cause.
• The modularity – smaller RBAT stages for seeding/oscillation, larger REA stages for amplification, and eDrive laser diode drive electronics for tailored pulse duration – provides flexibility to tailor each laser’s output parameters (pulse energy, burst duration, repetition rate) to specific application requirements.

To explore available RBAT and REA configurations and related drive electronics, visit our laser gain modules catalog.

Approved for Public Release: NG25-2258. © 2026 Cutting Edge Optronics, Inc.

Cutting Edge Optronics (CEO) recently built and tested one of their industry standard REA diode-
pumped solid-state (DPSS) laser modules with an Er:YAG rod as the gain medium and pumped with in-house-manufactured 97Xnm laser diodes. The Er:YAG rod was provided by Northrop Grumman
SYNOPTICS. The module’s laser emission wavelength is 2.94μm, which is highly absorbed by water
and hydroxyapatite. A laser at this wavelength has a variety of applications in the medical and
scientific laser communities such as dental surgery, wart removal, the cutting of bone and soft
tissue, as well as for pumping mid-wave IR lasers.

Test results from an REA module with a 5mm diameter rod and quasi-continuous-wave (QCW)
pumping of the laser diodes are shown below. The gain of Er:YAG is much lower than typical Nd:YAG
systems. The best output coupler reflectivity to maximize output power was 95% in a short cavity of
280mm length with a flat high reflector. Fluorescence imaging of the 2.94um emission showed
good uniformity of absorbed diode light (see Figure 1.) Imaging the output coupler, a uniform beam
profile was observed (see Figure 2.)

Figure 3 shows output energies per pulse obtained during short cavity testing for various pulse
widths. With the same duty cycle, the module was tested at 500μs, 1ms, and 1.5ms. Efficiencies of
pump energy to output energy of 19%, 22%, and 18% were obtained for 500μs, 1ms, and 1.5ms
respectively. The energy level dynamics of the Er:YAG system is complex. Due to thermally driven
effects, the tail end of the optical pulse fell off for pulse widths longer than 1ms. This explains the
reduction in efficiency for 1.5ms pulses. At 15Hz and 1ms, a maximum average output power of
70W was obtained. The maximum output energies per pulse obtained for 500μs, 1ms, and 1.5ms
were 2J, 4.67J, and 5.66J, respectively.

Due to the high quantum defect in Er:YAG, thermal lensing is an important consideration when
building an Er:YAG laser. The power of the thermal lens in this module was measured to be 0.012
diopters per watt of average pump power plus a baseline of 0.173 diopters above the threshold.
The successful testing of a new Er:YAG, 5mm diameter side pumped rod laser module was
performed, with output pulse energies of up to 5.5J and average powers exceeding 50W achieved.
This module is based on the CEO’s industry-proven REA laser module series designs used for the past
several decades as oscillators and amplifiers in a variety of DPSS laser applications. These
modules are typically rated for lifetimes greater than 10 billion pulses, which exceeds the projected
lifetime of medical equipment in many environments.

Approved for Public Release: NG25-0073. © 2025 Cutting Edge Optronics, Inc.