Confirming the pulse-bandwidth-product for fs laser pulses

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In summary, the conversation discusses measuring the pulse duration of a mode locked Ti:Sa laser using an autocorrelator. The pulse duration was determined to be 132 fs for a central wavelength of 800 nm and spectral bandwidth of 8 nm. The individual is trying to confirm the inequality Δt * Δf ≥ 0.44, but is having trouble due to the deconvolution factor and calculations for Δf. They are seeking help to determine if the issue is with the setup or the autocorrelator. It is suggested to move the discussion to an advanced physics forum.
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mamoamamoa
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Hey everyone,
hope this is the right place to ask this question so I'll just put it out here.

I've been measuring the pulse duration of a mode locked Ti:Sa laser with an autocorrelator. For a central wavelength of λ_0 = 800 nm and the spectral bandwidth of the Ti:Sa Laser (FWHM) Δλ = 8 nm, the Gauss fitted autocorrelator funtion gave me a pulse duration of (FWHM) Δt = 132 fs. I'm trying to confirm that Δt * Δf ≥ 0.44.

Δt needs to be deconvoluted by a factor of 1/√2 for a Gaussian pulse shape and Δf should be given by Δf = Δλ * c / (λ_0)^2, which would give me 0.35 and that can't be true. Any help is really appreciated. Thanks,

Mamoa

Edit: Δλ and λ_0 are pretty stable so I'm not worried about those. That means either my pulses are not Gauss shaped (setup problem) or I'm measuring the wrong pulse durations (autocorrelator problem), would you agree?
 
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I would move this to the advanced physics forum.
 

1. What is the pulse-bandwidth product for fs laser pulses?

The pulse-bandwidth product is a measure of the temporal duration of a laser pulse and the spectral bandwidth of the laser. It is calculated by multiplying the full width at half maximum (FWHM) of the pulse in time by the FWHM of the pulse in frequency. This value is important for characterizing ultrafast laser pulses and understanding their potential applications.

2. Why is it important to confirm the pulse-bandwidth product for fs laser pulses?

The pulse-bandwidth product is a critical parameter for determining the quality and performance of a laser system. By confirming this value, scientists can ensure that the laser is producing the desired pulse shape and duration, which is crucial for experiments and applications in fields such as spectroscopy, microscopy, and laser machining.

3. How is the pulse-bandwidth product for fs laser pulses typically measured?

The pulse-bandwidth product can be measured using a variety of techniques, including interferometry, autocorrelation, and spectral phase interferometry for direct electric-field reconstruction (SPIDER). These methods involve splitting the laser pulse and measuring the time delay or phase shift between the different components to determine the pulse duration and spectral bandwidth.

4. What factors can affect the pulse-bandwidth product for fs laser pulses?

The pulse-bandwidth product can be affected by various factors, such as the type and quality of the laser components, the laser's operating conditions, and environmental factors. For example, changes in temperature or vibrations can cause fluctuations in the pulse duration and spectral bandwidth, leading to variations in the pulse-bandwidth product.

5. How can scientists optimize the pulse-bandwidth product for fs laser pulses?

To optimize the pulse-bandwidth product, scientists can carefully select and align the laser components, such as the laser cavity and pulse stretcher, to minimize any distortions or losses. They can also monitor and adjust the laser's operating parameters, such as the pump power and cavity length, to achieve the desired pulse duration and spectral bandwidth. Additionally, environmental conditions should be controlled and monitored to minimize any potential sources of noise or instability in the laser system.

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