Femtosecond streak camera

On the Osaka University thermionic cathode L-band linac, a time resolution of two picoseconds was achieved using magnetic pulse compression and time jitter compensation systems (Fig. 13). The time jitter between the Cerenkov light from the electron beam and the laser pulse was measured shot-by-shot with a femtosecond streak camera to accurately determine the relative time of each measurement in the kinetic trace. In this way, the time jitter that would otherwise degrade the time resolution was corrected, and the remaining factor dominating the rise time was the electron-light velocity difference over the 2-mm sample depth. 

Watanabe T, Sugahara J, Yoshimatsu T, Sasaki S, Sugiyama Y, Ishi K, Shibata Y, Kondo Y, Yoshii K, Ueda T, Uesaka M. (2002) Overall comparison of subpicosecond electron beam diagnostics by the polychromator, the interferometer and the femtosecond streak camera. Nuel Inst Meth A 480 315-327. 

M. Uesaka, T. Ueda, T. Kozawa, T. Kobayashi, Precise measurement of a subpicosecond electron single bunch by the femtosecond streak camera, Nucl. Inst. Meth. Phys. Res. A 406 (1998) 371. 

Fig. 6.64 Streak image of two subpicosecond pulses separately by 4 ps, measured with the femtosecond streak camera [761]...

In commercial streak cameras the deflection speed can be selected between 1 cm/50 ps to 1 cm/10 ns. With a spatial resolution of 0.1 nm, a time resolution of 1 ps is achieved. A femtosecond streak camera has been developed [761] that has a time resolution selectable between 200 fs to 8 ps over a spectral range 200-850 nm. Figure 6.64 illustrates this impressive resolution by showing the streak camera screen picture of two femtosecond pulses which are separated by 4 ps. Recent designs even reach a resolution of 200 fs. The spatial separation depends on the sweep voltage ramp. More details can be found in [760, 761, 763, 764]. 

C. H. Lee, Picosecond Optoelectronic Devices (Academic Press, New York, 1984) Hamamatsu, FESCA-200 (Femtosecond Streak camera C6138, information sheet, August 1988) and acmal information under http //usa.hamamatsu.com/sys-streak/guide.htm... 

Hamamatsu FESCA (Femtosecond Streak camera 2908, information sheet, August 1988)... 

The time-resolved techniques that are usually used for FLIM are based on electronic-basis detection methods such as the time-correlated single photon counting or streak camera. Therefore, the time resolution of the FLIM system has been limited by several tens of picoseconds. However, fluorescence microscopy has the potential to provide much more information if we can observe the fluorescence dynamics in a microscopic region with higher time resolution. Given this background, we developed two types of ultrafast time-resolved fluorescence microscopes, i.e., the femtosecond fluorescence up-conversion microscope and the... 

During recent years the development of fast photodetectors has made impressive progress. For example, PIN photodiodes (Sect. 4.5) are available with a rise time of 20 ps [11.100]. However, until now the only detector that reaches a time resolution slightly below Ips is the streak camera [11.101]. Femtosecond pulses can be measured with optical correlation techniques, even if the detector itself is much slower. Since such correlation methods represent the standard technique for measuring of ultrashort pulses, we will discuss them in more detail. 

To study the carrier and vibrational relaxation dynamics, mode-locked laser systems, which provide femtosecond pulses and fast and sensitive detection systems are necessary. For detection, streak cameras are used for measurements with time resolution in the subpicosecond range or CCD cameras for time-integrated measurements. For the latter, time resolution can be achieved by using optical Kerr gates or upconversion [266,268]. In general, the two mainly used optical detection mechanisms for coherent phonons (optical, acoustical, or LO-plasmon coupled modes) are the pump/probe [280-285] and the four-... 

Time resolved fluorescence measurements have been used for decades because they are such a powerful tool to investigate fluorophore-metal composites. Due to insufficient time resolution, mostly long lived luminescence like that from triplet states has been investigated. When fluorophOTes are attached to metal nanostructures, fluorescence decay times are in the sub nanosecond time range. To measure those dect times accurately, techniques such as time correlated single photon counting, frequency domain fluorescence measurements, streak camera measuremets, and femtosecond pump SHG-probe have been used. 

Another option for performing time-resolved nonlinear Raman spectroscopy is to use a fast detector such as a streak camera. By combining short picosecond or femtosecond pulses with longer nanosecond pulses, a generated signal can be produced that evolves over time. This approach can be used to obtain simultaneously both frequency and time domain information. 

Lifetimes shorter than a nanosecond can be measured using picosecond lasers with suitable detectors (streak camera) [3], bearing in mind that, as a rule of thumb, the cost of the equipment is inversely proportional to its time resolution. However, the measurement of lifetimes shorter than a nanosecond is most commonly performed with a single photon apparatus (see Sect. 7.2.3). Lasers with pulse duration shorter than 100 femtoseconds (1 fs = 1 x 10 s) are also available, but with such equipment the sample emission eannot be monitored for technical reasons, and transient absorption must be measured instead (see Chap. 8). 

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