Recent content by cev1

At that focal length, the lens quality is virtually irrelevant to spot size assuming: 1. Your beam size at the lens is much smaller than your focal length (less than a factor of 10, say). 2. you aren't using a drinking glass.

Is there some reason why the 1550 and 1650 laser diodes are not acceptable? Thorlabs stocks them at 300mW and 225 mW, respectively. There are countless fiber lasers available in this range producing watts of power.

Don't overlook the Titanium Sapphire (TiS) laser, which is broadly tunable from 650-1050nm. I'm not aware of anything else with such a broad gain profile. If you pulse a TiS laser at a high rep rate, it is "pseudo-CW" and can be single-pass frequency doubled/tripled to cover interesting parts...

A laser is certainly not your best light source for your application. They are expensive (even if your color was obtainable), low power, and highly non-uniform. The uniformity is especially important if you are trying to make a "standard" for grading something like a diamond. Speckle induced by...

We have 375nm LD's. The longer-wavelength fluorescence generally overwhelms the fundamental in a typical viewing scenario. We generally view this as a good thing since we can easily see the beam.

This was actually a subject of great interest during the legal wars over the original laser patents. Someone was trying to patent stimulated emission, so the opponents had to show that it existed in nature. At the time there was some thought that stimulated emission occurred in the outer...

Virtually everything you "see" below 400 nm is fluorescence. Your retina and vitreous humour fluoresce at these wavelengths, so you can't even make an honest judgement whether you are "seeing" 400nm or something redder. This effect is especially pronounced if you have a very tiny source, like...

Sorry, took me a whole two weeks to finally bring the metric allen keys back to my desk. The yellow plate is aluminum, just like the rest of the housing. It is hard to tell from the photos, but the brass heat sink is spaced by a couple of mm from the yellow plate. All the wires pass through this...

Wouldn't shine a "powerful" anything laser into a cut diamond without some eyewear. OP is confusing power with intensity. Lasers have extreme intensity (power per solid angle) but very low power. Fluorescence is a linear process, and therefore depends only on the power delivered to your rock...

Since all three colors are visible and roughly the same power and damage mechanism, they will act roughly the same as any single color of the sum power. There is a slight caveat for specular reflections: It depends somewhat on how precisely the three colors are aligned. The spot formed on your...

LED rather than LD. I have a Spectroline UV-4BNF 254/365nm black lamp for looking at minerals. Do you have any feel for how the flashlight compares to the blacklamp? I remember seeing at least one working tripled YAG in the $1K range. These are pulsed lasers, so the peak power is huge and the...

They are too big to post, so here are some links: front 1 front 2 back 1 back 2 Not all the best quality pictures, but good for now.

To my knowledge, nothing below 370nm is available commercially yet. There are publications on diodes working in the 340nm range, but these are research efforts. The materials are all understood to produce diodes down into the 200nm range. The secret sauce is removing imperfections to the level...

It is trivial to remove the purple part. There are three screws around the edge, Then just a little bit pf prying. There is no risk since it not attached to anything of importance in the device (the same is true for the back cover, although it took a lot more prying since there is no edge to...

You can look here: University of Maryland Trapped Ion Quantum Information Group Ca, Sr, Ba, Yb are most relevant. These elements have near-UV dipole transitions (blue arrows in the charts) and near-UV neutral S-P transitions (in text below each chart). Because temperature tuning is very poor...