A new mechanism of controlling the absorption of high-intensity signal light with frequency $\omega $ω and intensity ${j_\omega }$ jω by complementary control light with frequency $\Omega \gt {2}\omega $Ω>2ω and 2 or 3 orders of magnitude lower intensity ${j_\Omega }$ jΩ is proposed. The mechanism is based on the photon avalanche effect in quantum wells. The electron concentrations in size-quantization subbands and conduction band continuum and the absorbed power of signal light are obtained as functions of the intensities ${j_\omega }$ jω and ${j_\Omega }$ jΩ and the time of exposure to laser radiation $t$ t. It is established that the resulting dependences exhibit well-pronounced threshold behavior. For example, at ${j_\Omega }\;\sim\;{0.2 - 1}\;{\text{kW/cm}^2}$ jΩ∼0.2−1kW/cm2 and $t\;\sim\;{0.1 - 5}\;\text{ns}$ t∼0.1−5ns, it is possible to control the absorption of signal light, so that the absorption of this light is practically lacking at intensities ${j_\omega }$ jω below the threshold intensity (${40 - 200}\;{\text{kW/cm}^2}$40−200kW/cm2) and becomes very strong at intensities above the threshold intensity. The case when control light $\Omega $Ω is the third harmonic of high-intensity signal light is also considered.A new mechanism of controlling the absorption of high-intensity signal light with frequency $\omega $ω and intensity ${j_\omega }$jω by complementary control light with frequency $\Omega \gt {2}\omega $Ω>2ω and 2 or 3 orders of magnitude lower intensity ${j_\Omega }$jΩ is proposed. The mechanism is based on the photon avalanche effect in quantum wells. The electron concentrations in size-quantization subbands and conduction band continuum and the absorbed power of signal light are obtained as functions of the intensities ${j_\omega }$jω and ${j_\Omega }$jΩ and the time of exposure to laser radiation $t$t. It is established that the resulting dependences exhibit well-pronounced threshold behavior. For example, at ${j_\Omega }\;\sim\;{0.2 - 1}\;{\text{kW/cm}^2}$jΩ∼0.2−1kW/cm2 and $t\;\sim\;{0.1 - 5}\;\text{ns}$t∼0.1−5ns, it is possible to control the absorption of signal light, so that the absorption of this light is practically lacking at intensities ${j_\omega }$jω below the threshold intensity (${40 - 200}\;{\text{kW/cm}^2}$40−200kW/cm2) and becomes very strong at intensities above the threshold intensity. The case when control light $\Omega $Ω is the third harmonic of high-intensity signal light is also considered.

Journal of the Optical Society of America BOct 22, 20191 citation

Limits of Light Absorption

WORLD SCIENTIFIC eBooksJul 27, 20220 citations

Absorption and Emission of Light

Wolfgang Demtröder

Springer eBooksJan 1, 20149 citations

Anomalous absorption of the ultrafast-laser supercontinuum

Davıd L. Andrews

The broad white-light continuum generated on the passage of ultrashort pulses of laser light through suitable media has found numerous applications in the physical, chemical, and biological sciences. Many of these are based on use of the continuum to probe the absorption characteristics of transient species, in order to obtain information on their decay kinetics. The processing of data from such experiments is generally based on the implicit assumption that the absorption of white light is subject to the normal Beer-Lambert law, in that the absorption at any particular frequency is linearly proportional to the intensity of the probe light at that frequency. In this paper it is shown that the validity of this underlying assumption should be seriously questioned. At high intensities, the uncertainty principle allows for photon pairs with differing frequencies to provide the energy for the cooperative excitation of molecules in close proximity. This nonlinear absorption, which depends on the frequency autocorrelation function and intensity of the continuum light, results in a rate of absorption which may depart significantly from the normal Beer-Lambert behavior. Hence the interpretation of continuum-probe experiments may need to be reexamined.The broad white-light continuum generated on the passage of ultrashort pulses of laser light through suitable media has found numerous applications in the physical, chemical, and biological sciences. Many of these are based on use of the continuum to probe the absorption characteristics of transient species, in order to obtain information on their decay kinetics. The processing of data from such experiments is generally based on the implicit assumption that the absorption of white light is subject to the normal Beer-Lambert law, in that the absorption at any particular frequency is linearly proportional to the intensity of the probe light at that frequency. In this paper it is shown that the validity of this underlying assumption should be seriously questioned. At high intensities, the uncertainty principle allows for photon pairs with differing frequencies to provide the energy for the cooperative excitation of molecules in close proximity. This nonlinear absorption, which depends on the frequency autocorrelation function and intensity of the continuum light, results in a rate of absorption which may depart significantly from the normal Beer-Lambert behavior. Hence the interpretation of continuum-probe experiments may need to be reexamined.

Physical Review ANov 1, 19889 citations

Optical switching effects using excited state absorption of Er3+ ‐doped fibers

Yoshinobu Maeda, Masatoshi Migitaka

Abstract When a 787‐nm signal light with constant optical intensity is superimposed with a control light of the same wavelength in an Er‐doped optical fiber, optical switchoff occurs. The optical intensity of the control light for switch‐off is 1.4 and 25 W/cm2. As the optical intensity increases, the optical transmission of the fiber decreases. When the optical intensity is 25 W/cm2, the optical transmission is lowest. A numerical analysis based on the four‐level double absorption model indicates that this nonlinear transmission characteristic takes place because the excited absorption due to the 2H11/2‐4I13/2 transition of Er3+ is predominating in the 4I9/24I15/2 and 2H11/2‐4H13/2 double absorptions. The optical switch‐off phenomenon is regarded as the first‐order phase transition phenomenon due to complex saturable absorbers with negative optical intensity dependence in optical transmission.Abstract When a 787‐nm signal light with constant optical intensity is superimposed with a control light of the same wavelength in an Er‐doped optical fiber, optical switchoff occurs. The optical intensity of the control light for switch‐off is 1.4 and 25 W/cm2. As the optical intensity increases, the optical transmission of the fiber decreases. When the optical intensity is 25 W/cm2, the optical transmission is lowest. A numerical analysis based on the four‐level double absorption model indicates that this nonlinear transmission characteristic takes place because the excited absorption due to the 2H11/2‐4I13/2 transition of Er3+ is predominating in the 4I9/24I15/2 and 2H11/2‐4H13/2 double absorptions. The optical switch‐off phenomenon is regarded as the first‐order phase transition phenomenon due to complex saturable absorbers with negative optical intensity dependence in optical transmission.

Electronics and Communications in Japan (Part II Electronics)Jan 1, 19920 citations

Absorption and Emission of Light

Stephen P. Martin

Graduate texts in physicsJan 1, 20260 citations

A new mechanism of controlling the absorption of high-intensity signal light with frequency $\omega $ω and intensity

{j_\omega }

jω by complementary control light with frequency $\Omega \gt {2}\omega $Ω>2ω and 2 or 3 orders of magnitude lower intensity

{j_\Omega }

jΩ is proposed. The mechanism is based on the photon avalanche effect in quantum wells. The electron concentrations in size-quantization subbands and conduction band continuum and the absorbed power of signal light are obtained as functions of the intensities

{j_\omega }

jω and

{j_\Omega }

jΩ and the time of exposure to laser radiation

t

t. It is established that the resulting dependences exhibit well-pronounced threshold behavior. For example, at

{j_\Omega }\;\sim\;{0.2 - 1}\;{\text{kW/cm}^2}

jΩ∼0.2−1kW/cm2 and

t\;\sim\;{0.1 - 5}\;\text{ns}

t∼0.1−5ns, it is possible to control the absorption of signal light, so that the absorption of this light is practically lacking at intensities

{j_\omega }

jω below the threshold intensity (${40 - 200}\;{\text{kW/cm}^2}$40−200kW/cm2) and becomes very strong at intensities above the threshold intensity. The case when control light $\Omega $Ω is the third harmonic of high-intensity signal light is also considered.