Calculation of total tuning range
In the field of precision measurement, especially in the field of atomic and molecular photophysics, the tuning range of the laser is particularly important.，If the wavelength cannot be tuned to the specified wavelength, the light and atoms cannot interact, and the expected experimental effect cannot be achieved.Precilasers' products can cover an ultra-wide range of 200-4500nm. Most products are realized through nonlinear frequency conversion such as frequency doubling and frequency conversion, so careful calculation of the tuning range is required.
Conversion between tuning wavelength and tuning frequency
According to the relationship between wavelength and frequency：
Available：
l For example, a 1550nm fiber DFB laser has a tuning range of 1nm, and the corresponding tuning frequency is 124.78GHz. The tuning range of a 1550nm FECL is 7GHz, corresponding to 0.056nm.
Tuning range of frequency-doubled lasers
After the laser is frequency doubled, the tuning frequency is twice the tuning range of the fundamental frequency light, and the tuning wavelength is half the tuning wavelength of the fundamental frequency light.
l For example, the tuning range of a 1560nm FECL seed laser is 7GHz. After frequency doubling to 780nm, the tuning range is 14GHz.
l The tuning range of the 1560nm fiber DFB seed laser is 1nm, and the tuning range after frequency doubling to 780nm is 0.5nm
Tuning range of sum frequency lasers
The tuning range of a sum frequency laser is the sum of the tuning frequencies of the two fundamental frequencies.
l For example, the 840nm laser output is a 1.5um FECL seed laser and a 1.8um thulium-doped fiber DFB seed laser, and their respective tuning ranges are 7GHz and 83GHz. Therefore, after frequency summing, the tuning range is 90GHz, and the corresponding tuning wavelength is: 0.2nm
Tuning range of sum frequency doubled lasers
(Tuning frequency of fundamental light 1 + tuning frequency of fundamental light 2)*2
l For example, a 420nm laser is a frequency doubled 840nm laser, and the tuning range of the 840nm laser is 90GHz, so the tuning range of the 420nm laser is 90GHz*2=180GHz.
Tuning range of difference frequency laser
The tuning range of the difference frequency laser = the tuning frequency of fundamental frequency light 1 + the tuning frequency of fundamental frequency light 2. Note that this is not a subtraction relationship.
When calculating the tuning range of a laser, you should pay attention to:
1.The tuning range is related to the tuning range of the seed laser. If the laser has the same wavelength, the tuning range is different for a 1.5um fiber DFB laser or FECL seed.
2. The tuning range is related to the operating wavelength range of the amplifier.
3. The tuning range is also limited by the crystal of nonlinear frequency conversion. For example, the temperature tuning bandwidth of a 509nm crystal is 5nm, and the temperature tuning bandwidth of a 302nm-313nm crystal is 1nm.