Does there exist a laser that is tunable over the whole visible spectrum? If so does there exist one that is solid state? This is to settle a score with my dumb workmates.
The Coherent Chameleon titanium-sapphire laser tunes over a pretty enormous range, mostly in the IR (680 to 1080 nm). With a frequency doubling crystal, it covers most of the visible (340 to 540 nm), and if you add an OPO, it can tune over the entire visible range with frequency doubling.
Supercontinuum sources cover the entire visible spectrum simultaneously, and are often operated with post-filtering if you want narrowband light.
Toptica's iChrome is a narrowband source that tunes over the entire visible by following supercontinuum generation with frequency doubling.
All these lasers are solid-state.
Now, regarding the spirit of your question. Does your bet with your dumb co-workers allow nonlinear optics like supercontinuum generation or frequency doubling? Does it allow mixtures of different gain media? Are you specifically curious about semiconductor lasers? Do you care about the coherence of the output, the bandwidth, or the brightness?
Georg is correct. The free electron laser is tunable:
But it is not a lasing that can be used in a pointer or a portable method. It needs accelerated electrons. So it depends what sort of argument you have with your friend.
For comparison, this company Radiantis sells OPOs that are tunable over almost the whole visible spectrum. OPOs are not lasers, but they are sources of coherent light which use a solid state gain medium.
Full disclosure: I do not work for and have never done business with Radiantis, but I have toured their lab once.
protected by Qmechanic♦ Oct 20 '13 at 10:23
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