What is 785 nm laser?
The most commonly used wavelength in Raman spectroscopy is 785 nm. It offers the best balance between scattering efficiency, influence of fluorescence, detector efficiency and availability of cost-efficient and compact, high-quality laser sources. There is a number of different kinds of lasers available at 785 nm.
Which laser of high efficiency is?
With 450 W quasi-CW stacked laser diode bars pumping at 1064 nm, 236 W optimum output laser at 1064 nm was obtained. The optical-to-optical conversion efficiency was 52.5% and corresponding slope efficiency was 62%. This is up to now the highest slope-efficiency acquired in high power Nd:YAG ceramic laser.
What is Laser Diode nm?
Laser diodes, which are capable of converting electrical current into light, are available from Thorlabs with center wavelengths in the 375 – 2000 nm range and output powers from 1.5 mW up to 3 W.
What is the advantage of using a 532 nm laser as the excitation source of a Raman microscope compared to using a 785 nm laser as the excitation source?
As an example, Raman scattering at 532 nm when compared to 785 nm is a factor of 4.7 more efficient and is 16 times faster than at 1064 nm.
Can a laser have 100% efficiency?
If you have perfect gain medium, and perfect mirrors, you will achieve a perfectly 100% energy efficient laser. This is to say that 100% of your electrical input is converted to photons.
What advantage is there to using a 785 nm diode laser as compared to a 1064 nm laser as a Raman excitation source?
The shorter wavelengths of the near-IR lasers result in higher signal levels. For example, a 785 nm laser gives 3½ times increased sensitivity—when compared with the 1.064 µm laser of a FT-Raman system—because of the ν4 scattering efficiency dependency.
Do lasers pulse?
Some lasers emit pulses with a constant pulse repetition rate. In case of Q-switched lasers, this is often between 10 Hz and 100 kHz, while mode-locked lasers emit with very high repetition rates, typically tens or hundreds of megahertz, sometimes even many gigahertz. The energy per pulse is correspondingly low.
Why is co2 used in lasers?
Carbon-dioxide (CO2) lasers are powerful and comparatively efficient gas lasers emitting at 10.6 µm or at other wavelengths around 9-11 µm. A gas discharge excites nitrogen molecules, which transfer their energy to the laser-active CO2 molecules.