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  • Users: silin
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  1. S

    Origin of notations in physics.

    Does anyone know a resource (book, website, etc.) where the origin of notations in physics is described? For instance it is clear that F comes from force, but it is not clear why c is the speed of light. I would like to find out how did people come up with the existing notations for physical...
  2. S

    Applications of optical devices in environmental science.

    Are there any applications of optical devices in environmental science? What technologies, companies and research groups are involved?
  3. S

    Cell phone, mp3 player in the lab

    Is it it safe for electronics in physics labs (spectroscopy devices, lasers, AFM, Teraherz microscope) to use: - cell phone - radio - mp3 player Can they cause any noise in electronics and distort signals from photon counting detectors or influence lasers somehow? I'm asking because our...
  4. S

    Where to study? (German speaking countries)

    I don't know much about the first two, but # University of Munich (LM Munich) # Technical Univeristy of Munich (TU Munich) # Swiss Federal Institute of Technology Zurich(ETH) are all excellent universities. Actully LMU and TU in Munich are the best in physics in Germany. After...
  5. S

    Help on optical aberrations needed

    Thank you for the replies. I have done what you said and found that the problem is in the microscope. Probably there is some dirt in it, but it's amazing that the pattern is so regular.
  6. S

    Clever way to write a thesis

    Hi everyone. Could you share your ideas on how to write a thesis in the most clever way. Does it first make sense to present your results, then discuss them writing theory at the same time or it´s better to write an introduction and literature review at first? Who has got what experience on how...
  7. S

    Help on optical aberrations needed

    Does anybody know what can be the reason for such an aberration of initially Gaussian shaped laser beam (see attached picture)? Optical elements in the light path: linearly polarized diode 470nm laser, single mode polarization conserving fiber, collimator, mirror, lens, round 50 micrometer...
  8. S

    Schools German universities

    A question to people from America: are any German universities known in America?
  9. S

    Circular polarized light

    How is it possible to tell that light is circularly polarized using half-wave plate and a linear polarizer?
  10. S

    Adjustment of optics resources

    Thank you, Claude. I have one more question: does anybody know how to make sure that a parallel laser beam goes exactly through the center of a convex lens without having a CCD camera or any fancy laser profile monitor? What I´ve tried so far is to project the widened beam (after convex lens) on...
  11. S

    Adjustment of optics resources

    I have a couple of concrete questions by now: - how to ensure that laser beam is exactly parallel to the edge of the optical table? - what are the options of centering the beam in Linos microbench system (I know about using a quadrant photodiode, iris diaphragms or pinholes in the light...
  12. S

    Anyone studying biophysics

    The main questions biophysics studies today are: - proteins folding - gene regulation - interaction of biomolecules to perform functions in cells - molecular structure of cell membranes - energy transfer in membranes - biological sensors - cell movement - neuroscience There are also...
  13. S

    Concerning lipid bilayers

    I´m doing my Master thesis on biophysics now. It´s a branch of science with certainly many perspectives. I´ve visited a Nobel prize winners meeting last year (as a student of course :)) and that´s what these guys told me. Since molecular biology is THE science now in the 21st century, they will...
  14. S

    Books about academic career

    Did anyone read any good books with advice on developing your academic career starting from grd school? Or everyone is just spontaneous or listening to what your prof says. I find that for people, who are not absolute geniuses it's necessary to know this kind of stuff to succeed in making a...
  15. S

    Eye safety with lasers

    You mean beamsplitter on the other end of the fiber? But what for if you can just direct it at the screen to see how bright it is. The problem is that when you just start with coupling at first you see just nothing. Are you supposed just to be turning the screws randomly till something comes out...
  16. S

    Eye safety with lasers

    Thank you for the information. I think in the lab I work they are not following safety with class IV lasers too, if you say even its reflection is dangerous, because these reflections are over the whole place there. And I didn't like that such bright and powerfull lasers aren't somehow put into...
  17. S

    Eye safety with lasers

    Well, you're right, I'm not too happy about my professor too, not having told me anything about the laser safety, that's whay I'm looking for this info myself. The PhD student who supervises my work also does the laser coupling this way (and actually his eyesight isn't very good as I notice)...
  18. S

    Eye safety with lasers

    Can you give a reference where to read more on the issue of laser safety? Thank you.
  19. S

    Eye safety with lasers

    I don't look directly into the beam coming from the laser head, but at the one coming from the optical fiber, in which I'm trying to couple the beam. If I measure the intensity of this light, it's about 0.1 mW at first, as soon as it get this big, I start to use my photometer. Is it still...
  20. S

    Eye safety with lasers

    It's the class III laser, there are two of them: one with 470nm wavelength, second with 635nm.
  21. S

    Eye safety with lasers

    A question to people coupling lasers to optical fibers. What is the power and exposure time of laser beam directed in the eye which is considered dangerous? The ones I´m currently working with are 15 mW. Are there any ways to couple laser beam to a fiber without having to look into another end...
  22. S

    Adjustment of optics resources

    Thank you for the reply. The mounts I´m using are microbench (Linos) and optical rail (Owis). I´ve checked the manufacturers you mentioned, only Melles Griot has some about laser beam positioning. I do use laser light. I´m actually specifically interested in adjustment of a self-made confocal...
  23. S

    Adjustment of optics resources

    Hi everyone, who knows where to find a good introduction into adjustment of optical components, like making sure that light correctly centered on a lens, so that there are no aberrations, adjustment of mirrors under certain angles and such. I've been looking for some advice on adjustment, but...
  24. S

    How to measure light wavelength exactly?

    Hi people, does anybody know what the simplest device that can be used to measure monochromatic light wavelength exactly? Thanks.