I am studying Lasers and frequency combs - and am not quite understanding something. I understand the working principle of a laser, and thought the Laser output frequency is just the energy gap between the E3: metastable state and the E1: lower level laser state, and the output frequency we will see is just E = E3-E1 = hv, where v is the frequency.

2014年2月18日 · If the frequency of one laser is known with precision (or is assumed to be the standard frequency), it is possible to directly measure the frequency of another laser whose frequency is within a few GHz of the standard laser, without measuring wavelengths. This is accomplished by shining both lasers onto a very fast photodetector.

There are two typical ways of generating two laser beams with a precise frequency offset from each other. The first requires you to have a specialized device known an an acousto-optic modulator (AOM). These devices create a standing pressure wave in a specialized crystal.

In summary, we are informed of how a laser, which emits red light of one frequency, only does so when it is permanently on. Turning it on or off causes nature to create new frequencies which somehow facilitate the wave being there when it's on, and not when it isn't.

2016年6月19日 · I am having some difficulty understanding the Pound-Drever-Hall frequency stabilisation technique, when locking a laser to a stable cavity. As far as I understand: We emit the laser frequency, f 0. This signal is modulated with sideband frequencies, f 0 ± f m. This is fired towards the Fabry-Perot cavity, which has a resonant frequency f c.

2024年4月6日 · The spectrum of the laser is a function telling you how much power (or power spectral density) the laser outputs at each frequency or wavelength. How many wavelengths can we see in it, and why? It depends on the laser. Some are single-mode, producing a spectrum consisting of only a single, narrow, band of wavelengths.

2019年5月16日 · The usage difference reflects the essentially noise-like nature of laser light relative to the modulation rate. The word intensity means average power, that is the variance of instantaneous amplitude, and is preferred when the underlying modulation is very slow relative to the natural fluctuation rate.

2020年6月10日 · $\begingroup$ I found this question because I was curious why the frequency doubler in a common green laser pointer couldn't be used to make another green laser pointer into a UV-C laser. Even if only a few percent of the power comes out as UV-C this could be very useful, as the only commercial UV-C laser I could find uses frequently doubling ...

2012年10月25日 · I was discussing laser cooling in class today and I understood that the main principle of the process is to tune a laser to a frequency lower than the absorbtion frequency of the atom and so only the atoms with a certain velocity will absorb the photons. These atoms then re-emit a photon in a random direction thus on average cooling the atom.

2022年10月20日 · As you run the laser and it heats up from the current, you may see the wavelength change. Depending on the structure of the laser it may mode hop and jump to another wavelength. Many laser diode controllers will also have a temperature sensor and thermoelectric device with a feedback loop to keep the temperature constant, or to tune the diode ...