Wavelength shifting in the visible spectrum

[yup]

What sorts of optical devices can be used to efficiently alter the wavelength of visible / near-visible light? I've looked a little bit at dye-sub lasers and electroluminescence, but neither seems particularly efficient. I'm looking for a device or technique that can spread a ray of, say, narrowband green light into a wider-bandwidth green without drastic power loss. (The center frequency need not remain constant). The application would be for video display. I'm not really seeking some kind of breakthrough technology; just wondering if there's a standard optical method of doing this sort of thing. Thanks for any ideas!

 

[IRstuff]

What exactly are you trying to achieve? "Wider-bandwidth" generally means lower spectral power, which means your end result might be a dimmer signal.

Additionally, most, if not all, wavelength conversion devices are highly non-efficient and you will take another intensity hit from that alone.

TTFN

 

[yup]

Thanks for your response. Lower spectral power and intensity would be ok, as long as the power in one desired band can be increased at the expense of other bands.

I'm trying to increase the efficiency of a color video projection system which uses a white (metal halide) light source. This system is based on a single liquid crystal display (LCD) screen, which relies on subtractive color filters. Only three specific wavelengths of light (red, green, blue) are usefully transmitted through the filters, and the other wavelengths are discarded. I'm trying to design a "light recycler" which effectively concentrates the source lamp's energy into the three desired bands.

An initial partial design (which might well be ridicuous :-] ) is to use a dispersion prism and a curved mirror with physical gaps at the three desired wavelengths. This would bandpass the portions of light energy at the desired wavelengths, and reflect the other wavelengths. If a spectrum-spreading optical element were inserted into this reflected light path, at least some energy could be shifted from the undesired bands into the desired bands. Even for sake of argument, is there any optical element which could perform this kind of spreading?

 

[IRstuff]

No.

TTFN

 

[yup]

I guess I've a lot to learn about optics... wish I'd started
earlier, since it's a very appealing field.

Thanks again for your replies!

 

[yup]

Could a frequency-doubling crystal be used?

 

[IRstuff]

NLOs are really only efficient at one wavelength, e.g. "peaky." Additionally, they're barely efficient at their peak wavelength as it is.

The bottomline is that if it was possible at all, someone would have done it already, and you'd know about it.

TTFN