Natural Science Forum / Physics / Optics / July 2006

Well, the title is a little un-scientific, but I am unsure as to how to
phrase this question!
Has anyone quantified how much the colours of objects change during
sunrise? For instance, would a red/orange object backlit by a rising

I'm looking for a He-Ne laser with 632.8nm wavelength and 10mW power.
Can anyone suggest me some reliable, reputative manufacturers ? Please
help me! Thank you!

I didn't manage to read or post anything here for the last 3/4 of a
year, but I guess many of you will still remember me. I had quite a
turbulent time, since I very seriously considered to start my own
company. Well into the preparations, I got an offer for an interesting

If I install the flat rear mirror of an argon laser the wrong way round,
so that the reflective surface is away from the cavity, will it act like
an etalon and improve the coherence length?
/Neil

Hello, I was wondering what methods there are to test the output of a laser
that should be in the 50mw range.  I am not looking for exact numbers just
general power output.  I realize there are several comercial devices for
just this but I am hoping there is an inexpensive ...

I got a cheap green laser pointer from Ebay (from Hong Kong). It works
great sometimes, but it also has a problem. Sometimes when I turn it on,
the beam is very bright, but four or five seconds later, the power goes
down and the beam is barely visible. If I turn it off, wait some ...

One side of a one-way mirror is reflective and the other side is
transparent.  Is it possible to make something which has one side
that's neither transparent or reflective and whose other side is
transparent?  eg. a one-way wall or something?

I have a 3 colour DJ laser system which I run off DMX.  It has built in
beam shows and patterns that can be selected by DMX
It also has an ILDA port but at the moment I really can't afford a
controller or software for it.

So here's the question of the day: Does anyone know what this thing is
supposed to do?:
http://tinyurl.com/zn6hl
I got it for the cost of shipping because the laser tube was broken.  The

I'm wondering if this might be some sort of infra red transmissive material.
The
bead is a bit strange though. Anyone got any ideas what this stuff is?
http://cgi.ebay.co ...

The below link depicts a single-atom laser
http://physicsweb.org/articles/news/7/9/10
For the one-atom laser, the medium is a cesium atom and the pump source
is another laser.

All laser pointers in the market use diode-lasers. What makes it so
difficult to make a pointer-sized free-electron laser?
Thanks,
Radium

I'm eager to get an adapter to allow photomicrography; it seems there
are only a few choices out there. I currently own a Coolpix 990, but I
would like the ability to utilize the adapter with my Nikon FE 35mm, as
well as with any future digital camera I might get.

Does anyone know the relationship between Zernike coefficient and the
fifth-order aberration? I could find the relationship about the
third-order but not the fifth.
Alex

I have a beam from a Universal 30 watt CO2 laser that is around 4mm diameter
at the laser exit and about 12mm x 8.5mm about 2 meters away.  I want to
build a flying optic laser gantry with this unit, with the travels of
roughly 1 meter by 1 meter.