Group velocity dispersion on two pulses of different lengths

AI Thread Summary
The discussion focuses on the calculation of group velocity dispersion (GVD) for two pulses of different lengths, specifically addressing the relationship between their durations. A participant initially miscalculates the ratio of pulse durations, leading to confusion about the equation's validity. The correct formulation involves comparing the durations of the two pulses, represented as τ01 and τ02, with τ01 being ten times τ02. The conversation highlights the importance of accurately setting parameters in GVD equations to avoid errors. Clarifying these relationships is crucial for understanding pulse behavior in dispersion contexts.
StudentonaOdyssey
Messages
7
Reaction score
1
Homework Statement
GER:
Zwei bandbreitenlimitierte Pulse mit derselben Mittenfrequenz durchtreten dasselbe transparente optische Bauelement mit einer Dicke von 1 cm und einer GVD von 50 fs2/mm. Der eine Puls ist beim Eintritt 10-mal so lang wie der andere. Welcher der beiden Pulse ist nach dem Durchtritt unmittelbar nach dem Element länger? Um wievielmal länger ist dieser Puls als der andere?
ENG:
Two bandwith-limited pulses with the same middle frequency pass through the same transparent optic component with a thickness of 1cm and a GVD (Group Velocity Dispersion) of 50 fs^2/mm. One pulse is 10-times as long as the other on impact. Which one of the pulses is longer directly after the component? How many times longer is this pulse than the other.
Relevant Equations
Bandwidth-Limit
$$\Delta \omega \cdot \Delta t >= C$$

Pulse length after propagation
$$\tau _p = \tau _0 \sqrt{1+\frac{z^2}{D^2}}$$

$$D= \frac{\tau_0^2}{2\cdot GVD}$$
$$\tau _{01} = 10 \tau _{01}$$
If I calculate ##\frac{\tau_{p1}}{\tau_{p1}}## and set z=d=1cm I do not know how to continue from there as I can't solve the equation without knowledge of τ0 for D.
$$\frac{\tau_{p1}}{\tau_{p1}} = \frac{\tau_{02} \cdot 10}{\tau_{02}} \sqrt{\frac{1+\frac{d^2 \cdot 4 \cdot GVD^2}{\tau _{02}^4 \cdot 10^4}}{{1+\frac{d^2 \cdot 4 \cdot GVD^2}{\tau _{02}^4}}}}$$
 
Last edited:
Physics news on Phys.org
isn't ##\tau_{p1}/\tau_{p1} = 1##? are we confusing something here?
 
Yes that is my mistake, it should have been

$$\frac{\tau _{p1}}{\tau _{p2}}$$
Same with the ratio

$$\tau _{01} = 10 \cdot \tau _{02}$$
 
Thread 'Collision of a bullet on a rod-string system: query'
In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
Back
Top