ISSN:0030-3909    

DOI:10.1080/713820746

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

ISSN:0030-3909    

DOI:10.1080/716099578a

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

ISSN:0030-3909    

DOI:10.1080/713820735

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

We consider second-harmonic generation by a non-linear crystal placed in an empty resonant cavity and pumped by an external coherent field. It was recently predicted that the stationary state loses its stability through a Hopf bifurcation when the input intensity reaches a critical value. A new amplitude self-modulated state then arises. We construct explicitly this new time-periodic solution and prove its stability in the vicinity of the transition point. As the input intensity is further increased, numerical investigations indicate a new transition to another time-periodic solution; this transition involves an hysteresis cycle. The two periodic solutions differ by the number of maxima in one period: at low input intensity, there is one maximum per period, whereas at high input intensity there are two.

ISSN:0030-3909    

DOI:10.1080/713820743

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The paper investigates the relationship between the analytic properties of fields in scattering processes, more specifically their zero locations and the corresponding object information. Each zero encodes a complex harmonic in the object space. The significance of asymptotic zeros is discussed. An optical method is described for locating the zeros. The significance of the zero description for optical problems is outlined.

ISSN:0030-3909    

DOI:10.1080/713820739

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The conventional concept of OTF cannot be applied to sampled imaging systems which exhibit aliasing effects. This paper shows that the concept can, however, be extended to this class of systems if the condition of isoplanatism is redefined, and if only a limited range of spatial frequencies is considered. Parameters to quantify the amount of aliasing are also suggested, and these can be easily measured at the same time as the OTF, and used with the OTF to give a full description of the image transfer characteristics of aliased, sampled systems.

ISSN:0030-3909    

DOI:10.1080/713820741

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The solution of the wave equation for the case of second harmonic beam (SHB) analysis of an ultrashort laser pulse consisting of two gaussian subpulses is given. Using the expressions obtained the temporal resolution of the SHB method is investigated for varying subpulse duration and separation.

ISSN:0030-3909    

DOI:10.1080/713820734

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

It is shown that an object, characterized by a radially dependent index of refraction, is uniquely determined by its complex valued natural frequencies.

ISSN:0030-3909    

DOI:10.1080/713820742

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

By complementing a pinhole to produce an isolated opaque spot, the light ordinarily blocked from the pinhole image is transmitted, and the light ordinarily transmitted is blocked. A negative geometrical image is formed, distinct from the familiar 'bright-spot' diffraction image. Anti-pinhole, or 'pinspeck' images are visible during a solar eclipse, when the shadows of objects appear crescent-shaped. Pinspecks demonstrate unlimited depth of field, freedom from distortion and large angular field. Images of different magnification may be formed simultaneously. Contrast is poor, but is improvable by averaging to remove noise and subtraction of a d.c. bias. Pinspecks may have application in X-ray space optics, and might be employed in the eyes of simple organisms.

ISSN:0030-3909    

DOI:10.1080/713820733

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

A quantum-mechanical model of multi-photon lasers is proposed for arbitrary degeneracy of the multi-photon processes of photon emission and absorption governing the interaction between the active medium and the radiation field. Equations of motion are derived for the mean values of the intensive, slowly varying operators essential to the description of the dynamics. Stationary solutions are found and their stability is studied proving the existence of a non-equilibrium first-order phase transition. The critical value of the inversion parameter required for laser action is shown to vary by a jump depending on the degree of degeneracy of the multi-photon processes of emission and absorption considered.

ISSN:0030-3909    

DOI:10.1080/713820745

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor