A two dimensional theoretical model for describing gain coefficient in N2-lasers and the model validity for CVL and excimer lasers

Hariri, A.; Sarikhani, S.

doi:10.1016/j.optcom.2010.12.092

Cited by 15 publications

(10 citation statements)

References 27 publications

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“…For the analytical approach we let g 0 (z)z = γ L (z) at the lasing threshold. γ L (z) is the power loss and it was found by numerical calculation that it can be expressed analytically to a good approximation by γ L (z) = γ max L e −bz , showing that the power loss reduces slightly along the z-direction [20]. As we found that b is very small, we may often say that γ L ≈ γ max L , where γ max L is the maximum power loss.…”

Section: Introductionmentioning

confidence: 60%

Study of the amplified spontaneous emission spectral width and gain coefficient for a KrF laser in unsaturated and saturated conditions

Hariri¹,

Sarikhani²

2013

Laser Phys. Lett.

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On the basis of a model of a geometrically dependent gain coefficient, the amplified spontaneous emission (ASE) spectral width was calculated analytically for the nearly resonant transition of ν ∼ ν 0 , and also numerically for a wide range of transition frequencies. For this purpose, the intensity rate equation was used under unsaturated and saturated conditions. For verifying the proposed model, reported measurements of the ASE energy versus the excitation length for a KrF laser were used. For the excitation length of l = 84 cm corresponding to single-path propagation, the ASE spectral width for the homogeneously broadened transition was calculated to be 6.28 Å, to be compared with the measured 4.1 Å spectral width reported for a KrF oscillator utilizing a two-mirror resonator. With the gain parameters obtained from the ASE energy measurements, the unsaturated and saturated gain coefficients for l = 84 cm were calculated to be 0.042 cm −1 and 0.014 cm −1 , respectively. These values of the gain coefficient are comparable to but slightly lower than the measured gain coefficient for laser systems of 80-100 cm excitation lengths reported from different laboratories.

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Section: Introductionmentioning

confidence: 60%

Study of the amplified spontaneous emission spectral width and gain coefficient for a KrF laser in unsaturated and saturated conditions

Hariri¹,

Sarikhani²

2013

Laser Phys. Lett.

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“…On the other hand, for improving the laser beam quality, enhancement of the laser output energy, and reducing the laser beam divergence, designs based on oscillator-amplifier(OSC-AMP) N2-lasers have also been proposed. These include TEA-TEA, TE-TE, and the combined TEA-TE oscillator-amplifier systems [1][2][3][4][5][6][7][8][9][10][11][12]. In a laser system consists of an OSC-AMP, in addition to achieving improvement in laserperformances, it gives also a method of probing the laser output extracted from amplifier as the input energy to the amplifier changes.…”

Section: Pumping Mechanism For a Nitrogen Lasermentioning

confidence: 99%

“…Following the rate equations given by Fitzsimmons et al Where , , x, y is the photon density corresponding to photonstraveling in the z-direction [9], is the photon lifetime in the amplifier.By introducing the equivalent OSC system, we have furtherassumedthat photon density inside the AMP section can be written as , x, y , 0, y z ! {…”

Section: One Dimensional Modelmentioning

confidence: 99%

Determination of Effective Photon Lifetime in Nitrogenic Laser in One and Two Dimension

Hosseinimotlagh¹

2014

Optics

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Abstract:Since one of the most valuable measurable parameters in laser, called effective cavity lifetime , gives useful information about laser, this paper aims to study the description of it dependency, , on geometrical characteristics of N 2 -laser, electrodes length and amplifier gap separation. First based on the studies carried out on it , an oscillator-amplifier laser is used which operates under moderate current density conditions; Then in order to obtain a theoretical relation for effective cavity lifetime and to demonstrate the mentioned dependency using rate equations, at first a one-dimensional method is used for the photon density. Since the answers of rate equations in an oscillator-amplifier laser are complicated, a single-oscillator based modelis offered to make rate equations simpler. In this model, at first it is supposed that the photon density of inner part of the amplifier could ben ph (z,t)= n ph (0,t) exp (g 0 (z)z), If n ph n ph (z,t), then rate equations are used for this density and since g 0 is a function of z or amplifier electrode length (Z l AMP ), the cavity effective life time is calculated for equivalent oscillator.Then ,Since most of studies carried out in one dimension , so for approaching to more actual system a two -dimensional method is used for the photon density. So, we consider Z andY, which Z is along amplifier electrodes length and Y is along gaps separation. Supposing that Z and Y are independent on the photon density, two independent relations can be considered for the photon density. In this step, 2-dimensional photon density could be regarded as:n ph (z,y,t) = n ph (z,t) n ph (y,t) . and then 2-dimensional effective cavity lifetime amount is obtained as:1 ‫ץ‬ ‫ץ‬ ‫ץ‬ ‫ץ‬ , This relation includes 2 independent values along the electrodes length (Z l AMP ) and gap separation (y d AMP ). It also demonstrates that the obtained 2-dimentional relation represents a perfect schema for lifetime behavior. The results of this calculation are consistent with other reported N2-laser effective cavity lifetime values measured under moderate current density conditions.

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“…We also made an analytical approach with considering that at the lasing threshold we can write g 0 (z)z = γ L (z), where g 0 (z) is the z-dependent small signal gain. With this realization, we managed to find an analytical expression for the gain coefficient for N 2 -lasers operating under optimum gas pressures at a constant input voltage, [20,21] which is expressed below…”

Section: Introductionmentioning

confidence: 99%

“…Although equation (3) was obtained for an N 2 -laser under its optimized operational gas pressure, but it was verified that it is capable to predict gain coefficients in self-terminating gas lasers such as excimer lasers, N + 2 , N 2 , F 2 , CVL reported from different laboratories. [21] About the study of the ASE phenomenon, on the other hand, for explaining the ASE output energy in a KrF laser, i.e., ε ASE versus l AMP , gain coefficients for different segmented excitation lengths were calculated and it is observed that the calculated ASE gain coefficients also obey an equation similar to Eq. (3).…”

Section: Introductionmentioning

confidence: 99%

Theoretical study of amplified spontaneous emission intensity and bandwidth reduction in polymer

Hariri¹,

Sarikhani²

2015

Chinese Phys. B

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Amplified spontaneous emission (ASE), including intensity and bandwidth, in a typical example of BuEH-PPV is calculated. For this purpose, the intensity rate equation is used to explain the reported experimental measurements of a BuEH-PPV sample pumped at different pump intensities from Ip = 0.61 MW/cm2 to 5.2 MW/cm2. Both homogeneously and inhomogeneously broadened transition lines along with a model based on the geometrically dependent gain coefficient (GDGC) are examined and it is confirmed that for the reported measurements the homogeneously broadened line is responsible for the light–matter interaction. The calculation explains the frequency spectrum of the ASE output intensity extracted from the sample at different pump intensities, unsaturated and saturated gain coefficients, and ASE bandwidth reduction along the propagation direction. Both analytical and numerical calculations for verifying the GDGC model are presented in this paper. Although the introduced model has shown its potential for explaining the ASE behavior in a specific sample it can be universally used for the ASE study in different active media.

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A two dimensional theoretical model for describing gain coefficient in N2-lasers and the model validity for CVL and excimer lasers

Cited by 15 publications

References 27 publications

Study of the amplified spontaneous emission spectral width and gain coefficient for a KrF laser in unsaturated and saturated conditions

Study of the amplified spontaneous emission spectral width and gain coefficient for a KrF laser in unsaturated and saturated conditions

Determination of Effective Photon Lifetime in Nitrogenic Laser in One and Two Dimension

Theoretical study of amplified spontaneous emission intensity and bandwidth reduction in polymer

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