Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It only takes a minute to sign up.
Sign up to join this community
Is there a device which takes as input the wavelength or frequency value and produces electromagnetic waves of the given wavelength or frequency using an emitter? It might be that the wavelength range of the device is limited to a "considerably large" part of the electro-magnetic (EM) spectrum, but can it cover the entire visible spectrum?
Splitting a white light source,and getting different wavelengths might be an option. But are there other better ones?
It mostly depends on which properties you want. Do you only need a specific wavelength or do you need narrow band coherent radiation? If it's the former you may use filament lamps which emits a thermal spectrum and then select your wavelength with a sufficiently narrow filter. Some solid state devices like LEDs can also be specifically made to emit around a required wavelength.
If you need a coherent source then you may need to correctly setup a laser that emits at your required wavelength. Some lasers (like the Nd:YaG laser) can be tuned in a broad range of frequencies, while you can also use nonlinear optics techniques like sum-frequency and difference frequency generation in order to achieve wavelengths that your source cannot achieve on its own.
