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Saturation of Inhomogeneous Line Profiles

If a monochromatic wave with frequency w and wave vector k is incident on a sample of molecules with a thermal velocity distribution, only those molecules which are Doppler shifted into resonance with the field can interact with the radiation field. When the resonance frequency 0) 2 = ( 2  [Pg.105]

Assume the wave vector k to be parallel to the z direction. Equation (3.75a) then reduces to [Pg.106]

Because of saturation the population density n (v2,)dv of the absorbing subgroup in the interval dv = 6ui/k around v = (co - 0)22)/k decreases while that of the upper state E2 increases correspondingly. This causes a dip in the population distribution n2(v ) (Bennet hole) and a corresponding peak in the distribution n2(v ) of the upper state (see Figs.3.16,17) [Pg.106]

The absorption probability for a molecule expressed by the absorption cross section a22(y,w) therefore depends on its velocity y and on the frequency 0) and wave vector k of the light wave. From the considerations above one obtains [see (3.70)] [Pg.106]

For the population difference An(v) = n (v) - n2(v) altered by the velocity-selective saturation, we derive from (2.84h) with An = AnQ/(l + S ), using the frequency-dependent saturation parameter S (v,oj) responding to (3.70), [Pg.107]

In Sect. 3.6 we have seen that the saturation of homogeneously broadened transitions with Lorentzian line profiles results again in a Lorentzian profile with the half width [Pg.436]

We will now discuss saturation of inhomogeneous line profiles. As an example we treat Doppler-broadened transitions which represent the most important case in saturation spectroscopy. [Pg.437]

The same result could have been obtained from (3.71) 4 = hvAiillan with [Pg.445]

For A21 = 10 s the relaxation due to diffusion out of the excitation volume can be neglected. At sufficiently low pressures the collision-induced transition probability is small compared to A21. [Pg.445]

265jjlW With the value A21 = lO s of Example 7.2, the saturation intensity drops to 38 W/m.  [Pg.445]

380 W/m. Focusing the beam to a focal area of 1 mm means a saturation power of only 265 pW With the value A21 = 10 of Example 2.3, the saturation intensity drops to 38 W/m. Focussing to 10 x 10 pm reduces the saturation power to 3.8 nW. [Pg.91]


Fig. 2.6 Saturation of an inhomogeneous line profile (a) Bennet hole and dip produced by a monochromatic running wave with co coq (b) Bennet holes caused by the two counterpropagat-ing waves for co coq and for o) = (joo dashed curve) (c) Lamb dip in the absorption profile o s( )... Fig. 2.6 Saturation of an inhomogeneous line profile (a) Bennet hole and dip produced by a monochromatic running wave with co coq (b) Bennet holes caused by the two counterpropagat-ing waves for co coq and for o) = (joo dashed curve) (c) Lamb dip in the absorption profile o s( )...
In Fig. 2.7 the differences in the saturation behavior of a homogeneous (Fig. 2.7a) and an inhomogeneous line profile are illustrated. For the inhomogeneous case two situations are illustrated ... [Pg.98]

Fig. 2.7 Comparison of the saturation of a homogeneous absorption line profile (a) and an inhomogeneous profile (b) in a standing-wave field, (c) The traveling saturating wave is kept 2ita) = a)o and a weak probe wave is tuned across the line profile... Fig. 2.7 Comparison of the saturation of a homogeneous absorption line profile (a) and an inhomogeneous profile (b) in a standing-wave field, (c) The traveling saturating wave is kept 2ita) = a)o and a weak probe wave is tuned across the line profile...
The frequency dependence of the gain coefficient a(v) is related to the line profile g(y — vq) of the amplifying transition. Without saturation effects (i.e., jfor small intensities), a(v) directly reflects this line shape, for homogeneous as well as for inhomogeneous profiles. According to (2.83) we obtain with the Einstein coefficienct Bik... [Pg.224]

In the case of a purely inhomogeneous gain profile, the different laser modes do not share the same molecules for their amplification, and no mode competition occurs if the frequency spacing of the modes is larger than the saturation-broadened line profiles of the oscillating modes. Therefore all laser modes within that part of the gain profile, which is above the threshold, can oscillate simultaneously. The laser output consists of all axial and transverse modes for which the total losses are less than the gain (Fig. 5.27a). [Pg.293]


See other pages where Saturation of Inhomogeneous Line Profiles is mentioned: [Pg.91]    [Pg.91]    [Pg.93]    [Pg.95]    [Pg.97]    [Pg.87]    [Pg.445]    [Pg.445]    [Pg.447]    [Pg.449]    [Pg.103]    [Pg.90]    [Pg.90]    [Pg.436]    [Pg.105]    [Pg.91]    [Pg.91]    [Pg.93]    [Pg.95]    [Pg.97]    [Pg.87]    [Pg.445]    [Pg.445]    [Pg.447]    [Pg.449]    [Pg.103]    [Pg.90]    [Pg.90]    [Pg.436]    [Pg.105]    [Pg.98]    [Pg.224]    [Pg.250]    [Pg.452]    [Pg.289]    [Pg.238]    [Pg.266]    [Pg.225]    [Pg.442]    [Pg.108]    [Pg.234]    [Pg.29]    [Pg.27]    [Pg.1060]    [Pg.41]   


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Inhomogeneity

Inhomogeneous lines

Inhomogenities

Line saturation

Saturation inhomogeneous

Saturation profiles

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