L5 Flashcards
1
Q
Group velocity
A
Speed of the “envelope” of a pulse.
2
Q
Group index
A
Ratio of the vacuum velocity of light to the group velocity in the medium.
3
Q
Zero-dispersion wavelength for fused silica
A
- Wavelength where group velocity dispersion is zero
- ~1.3 μm.
4
Q
Group velocity dispersion of fused silica
name numbers
A
- +35 fs2/mm at 800 nm
- -26 fs2/mm at 1500 nm.
5
Q
Fourier-transform limited pulse
A
Minimum pulse duration for a given optical spectrum.
6
Q
Chirp
A
Frequency changes with time due to non-linear phase dependence.
7
Q
Phase, group, and front velocities
A
- v_p = c/n’ > c in most glasses at X-ray frequencies.
- v_g = c/n_g
- v_front = c (information speed)
8
Q
Metamaterials
A
Can have: Negative index of refraction.
