Laser-induced fluorescence (LIF) is a spectroscopic technique used in many branches of science that require the study of structural properties, concentration or flow of molecules that are fluorescent in their nature. It consists in the excitation of molecules by the absorption of laser light with a specific wavelength, which results in spontaneous emission of light from these molecules after a few nano- to microseconds.
The emitted light has a longer wavelength than that of the excitation laser, so it can be easily detected. Compared to absorption spectroscopy, LIF has a much higher sensitivity and spatial resolution - parameters that are crucial for gas combustion measurements, flow cytometry or detection of nanoparticles, among many others.
Laser Diodes in Laser-Induced Fluorescence
Due to a broad range of available wavelengths and their narrow linewidth, laser diodes are an excellent source for high-sensitivity LIF systems. Their popularity has driven the price down - this allows for the construction of economic systems, which also don’t require high-cost elements like high-reflectivity mirrors or external cavities thanks to the laser diode construction. In recent years the availability of UV laser diodes has increased significantly, leading to the increased use of LIF spectroscopy in life sciences, especially in biomedicine.
Schematic of a basic LIF setup
Laser Beam Shaping
Depending on the type of measurement, different laser beam shapes are required. Light sheet fluorescence microscopy uses a very narrow, but tall “sheet” of light that only illuminates the observed section of the sample. This is especially useful when working with biological material, which can be damaged by intense beams. Similarly, flow cytometry requires a highly uniform beam to encompass the stream of molecules, otherwise the response would be different in different parts of the sample. It is therefore advantageous to use beam shaping optics that create a top-hat profile.
Two-axis Gaussian beam profile
Top-hat beam profile
Opt Lasers can provide a wide selection of wavelengths, output powers, beam shaping optics and packaging. Contact us to learn more about how we can tailor a module for your application.
Customizable Laser System Features
Our engraving and cutting industrial laser system units can be customized with respect to the following features:
- Various Optical Power Levels
- Different Industrial Laser Wavelength Options
- Customized TTL or Analog Input Voltage Range
- Increased Maximum Operating Temperature
- Custom Optics to Produce a Specific Focus Spot Size or Working Distance
- Special Shapes or Dimensions
- Private Label Options
Feel free to contact us if you would like to discuss your requirements for a custom industrial laser system product.