Near-Infrared Laser Diodes for Raman Spectroscopy

Physics, chemistry, life science, medicine, material science, pharmaceuticals, forensics, quality control – there is no doubt that Raman Spectroscopy is an incredibly effective technique used in a variety of industries and applications. However, despite its functionality and adaptability, it is not to be misinterpreted as a simple procedure. It is a highly advanced method that requires the best tools possible utilized with the proper know-how. It may not be hot in the news like VR or Lidar in autonomous vehicles and is sure to cause more than a few headaches for students, but Raman is not to be undervalued.

What is Raman Spectroscopy?

Raman Spectroscopy is the method often used to determine certain properties or characteristics of a material or substance by using a light-emitting source, e.g. single frequency mode laser diode to illuminate the material and gather information based on its vibrational frequencies. By illuminating the source with a single frequency mode laser diode, the light is absorbed, transmitted, reflected, or scattered. A particular wavelength and bandwidth of illumination by a laser diode source correspond to a characteristic Raman scatter ‘fingerprint’, allowing both elemental and molecular bond identification as well as foreign element identification.

What is Raman Scatter?

If light is scattered when reflected back, this results in a collision with inelastic photons often referred to as Raman scatter. Raman scatter signals are notoriously problematic due to the spontaneous nature of the scatter (low signal/intensity relative to Rayleigh scatter) and variability of molecules detected, also known as “noise”. The efficiency and accuracy of detection is largely dependent on the wavelength selection, wavelength bandwidth, and spatial resolution of the beam.

 

The Right Laser for the Job

Many different types of devices may be used for Raman applications, but single-mode laser diodes are some of the most common. This is due to their ability to identify targets more precisely within the scatter due to wavelength precision, ±3nm or less, and beam quality, particularly those with an integrated volume bragg-grating (VBG) for “wavelength locking”.

Typical output for single-mode laser diodes for Raman applications includes those at 785, 830, 980, and 1064nm with power up to 100mW and beyond. Tighter beam tolerance means better detection, specific wavelength selection in between may help identify what is otherwise unknown.

You’ve Got Options

Sheaumann’s high-power, single-mode devices have served Raman customers for decades, including those in the handheld device, defense, medical, and industrial markets. Single-mode power up to 350mW at any wavelength from 780-1070nm.

Some available options:

  • Volume bragg-grating (VBG)
  • Microlens (fast-axis collimator)
  • Low and high AR coating options
  • Custom packaging
  • Custom wavelength (780-1070nm range)
  • Custom wafer growth/foundry services

Sheaumann’s ability to tailor products to meet specific needs helps mitigate common risks associated with Raman Spectroscopy. Products are developed in the USA with vertically integrated processing and packaging to deliver reliable, fully customizable products. All of our R&D and production activities are efficiently housed in one centralized facility near Boston, giving us complete control over all processes and the flexibility to create custom solutions for OEMs with unique requirements. Due to our turn-key facility, we offer whatever packaging services you may need, either in addition to or independent of, our laser diode growing services.

We offer a selection of standard submounts and modules designed to fit into almost any system. However, custom packaging is available and can be designed and manufactured by our expert engineers to exactly your specifications for whatever project you have in mind.

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