Coherence saturation for energetic photons (abstract)

Journal Article · Sat Jul 01 04:00:00 EDT 1989 · Rev. Sci. Instrum.; (United States)

DOI:https://doi.org/10.1063/1.1140857· OSTI ID:5906949

Csonka, P L

There are two well-known methods to generate coherent x-ray photons: bound state x-ray lasers (BXL) and free electron x-ray lasers (FEXL). Both rely on induced photon emission. Because of the short lifetime of inverted states and high required energy densities for BXLs on the one hand, and strict tolerance specifications for FEXLs on the other, serious technological obstacles have yet to be overcome before a working device will be available for research purposes, particularly in the hard x-ray range. Coherence saturation is proposed here as an alternative method to generate coherent energetic photon beams. It does not make use of stimulated emission, therefore, it is not subject to the same technological and cost restrictions which have so far limited the effectiveness of BXLs and FEXLs in the short wavelength range. In fact, the method does not affect the process of photon emission at all: instead it rearranges the photon after they have been emitted, to achieve an increase in (transverse) coherence. The rearrangement is to be accomplished by dynamical optical means, i.e., by a collection of optical elements at least one of which is nonstationary. The speeds required are well within the range of present day technology. The method was devised primarily to facilitate certain interference experiments (e.g., holography) in the x-ray range. Correspondingly, its aim is to increase (first-order) transverse coherence. The special case will be discussed when only one optical element is nonstationary, and that is a rotating mirror. The transversely coherent intensity, /ital I//sub /perpendicular//, is defined as the number of photons crossing the (transverse) coherence area per unit time. Denoting by /ital I/ the total photon intensity, define the (degree of) transverse coherence as /ital C//sub /perpendicular//=/ital I//sub /perpendicular////ital I/.

• Research Organization: Institute of Theoretical Sciences, University of Oregon, Eugene, Oregon 97403-5203 (US)
• OSTI ID: 5906949
• Journal Information: Rev. Sci. Instrum.; (United States), Journal Name: Rev. Sci. Instrum.; (United States) Vol. 60:7; ISSN RSINA
• Country of Publication: United States
• Language: English

Related Subjects

440300* -- Miscellaneous Instruments-- (-1989)
47 OTHER INSTRUMENTATION
BREMSSTRAHLUNG
COHERENT RADIATION
ELECTROMAGNETIC RADIATION
ELECTRONS
ELEMENTARY PARTICLES
EQUIPMENT
FERMIONS
HARD X RADIATION
HOLOGRAPHY
IONIZING RADIATIONS
LEPTONS
MIRRORS
RADIATION FLUX
RADIATION SOURCES
RADIATIONS
SYNCHROTRON RADIATION
X RADIATION
X-RAY EQUIPMENT
X-RAY SOURCES