Gravity acts on particle with mass. Space, ie Vacuum, does not have massive particle. So how can gravity affect the space? How can it distort it?

Related to Astronomy and Gravity.

06 July 2014 502 14 View

How can a Fabry Perot Interferometer (FPI) measure pm (pico-meter) displacements, using a mirror made of atoms with sizes of nm?

06 July 2014 462 4 View

How to Eliminate cosine error and abbe error in LASER measurement system(for example Rhenishaw XL80)?

I like to do project in laser measurement system. My objective is to eliminate or reduce the cosine error, abbe error in Laser measurement system. I have Rhenishaw XL80 system. Please tell the...

28 February 2021 4,890 3 View

How can we limit artifacts caused by rotation in fiber photometry?

We are trying to run fiber photometry experiments for long time scales, but we get these sinusoidal artifacts that come up. We think they may be caused by twisting of the fiber optic subject...

25 February 2021 568 1 View

How to measure angle between laser travel path and machine axis in Laser Measurement system?

25 February 2021 1,987 3 View

How can I simulate the optical absorption spectrum of a biomaterial (like DNA or protein) in COMSOL?

I need to simulate the optical properties of a biomaterial, namely DNA, in COMSOL. Basically I need to simulate the IR absorption spectrum of a cylinder filled with a 'concentration' of DNA. I am...

21 February 2021 3,043 3 View

What is the reason of the received optical signal to be slimmed down in multi-mode fiber?

What is the reason of the received optical signal to be slimmed down in multi-mode fiber? I have 4 km multi-mode fiber

03 February 2021 1,105 10 View

Why it is not permissible to correct all 5 classical optical aberration (spherical, chromatic, coma, astigmatism, curvature of field) simultaneously?

When first order paraxial optics is expanded to third order optics (i.e. sin x~ x-x3/3! instead of sin x~x) , these 5 optical aberrations result in. What is the rigorous mathematical proof that,...

26 January 2021 8,666 4 View

Difference between Second-harmonic generation and Two-photon absorption?

Hello Dear Researchers, I am confused about the Difference between Second-harmonic generation and Two-photon absorption? Can anyone describe the two phenomena briefly in the physical picture? What...

24 January 2021 9,912 5 View

Is it possible that the single-pass absorption exceeds 50%?

Dear researchers It's well-known that the maximum light absorption of any structure can not be greater than 50%. Is it possible that the single-pass absorption exceeds 50%? How?

17 January 2021 2,335 7 View

What can cause laser beam polarisation fluctuations?

Dear colleagues, We have observed large fluctuations in laser power in our setup and traced them down to fluctuations in laser beam polarisation. Attached is a schematic of the relevant part of...

14 January 2021 7,505 4 View

How an unusual visual effect at the Monte Carlo casino can be obtained?

At the Monte Carlo casino, I saw an unusual advertising image. It rotated around a vertical axis and seemed suspended in the air; there was no screen behind it. The image was bright and colorful....

03 January 2021 9,119 5 View