An embodiment of the invention relates to a method for carrying out a time-resolved interferometric measurement comprising the steps of generating at least two coherent waves, overlapping said at least two coherent waves and producing an interference pattern, measuring the interference pattern for a given exposure time, thereby forming measured interference values, and analyzing the measured interference values and extracting amplitude and/or phase information from the measured interference values. In at least one time segment, hereinafter referred to as disturbed time segment, of the expo-sure time, the interference pattern is intentionally disturbed or destroyed such that the corresponding measured interference values describe a disturbed or destroyed interference pattern. In at least one other time segment, hereinafter referred to as undisturbed time segment, of the exposure time, the interference pattern is undisturbed or at least less disturbed compared to the disturbed time segment such that the corresponding measured interference values describe an undisturbed or less disturbed interference pattern. The measured interference values that were measured during the entire given exposure time, are filtered, wherein those interference values that were measured during the at least one disturbed time segment, are reduced, suppressed or discarded. The filtered interference values are analyzed and the amplitude and/or phase information is extracted from the filtered interference values.

The present disclosure discloses a method and apparatus for preparing a femtosecond optical filament interference direct writing volume grating/chirped volume grating. The method is characterized in that optical filaments are formed in glass by using femtosecond pulse laser, and plasma is controlled to quickly scan in the glass and etch a volume grating or chirped volume grating structure by adjusting the focal length of convex lens, laser energy and movement of motor machine. The apparatus includes a femtosecond pulse laser module, a pulse chirp management module, a pulse time domain shaping module, a laser separation and interference module, a glass volume grating processing platform module and a camera online imaging module.

A method for observing a sample by lensless imaging, in which a sample is positioned between a laser diode and an image sensor, the laser diode being supplied with a supply current whose intensity is less than or equal to a critical value. This critical intensity is determined during preliminary operations, during which the intensity is initially greater than a laser threshold of the diode. By observing the image formed at the image sensor, the intensity is decreased until an attenuation of the interference images on the formed image is observed, the critical intensity corresponding to the intensity at which this attenuation is optimum.

Apparatuses and methods for comparative holographic imaging to improve structural and molecular information of reconstructions is disclosed herein. An example method at least includes acquiring a plurality of holograms of a sample, wherein each hologram of the plurality of holograms is acquired at a different electron beam energy, and determining atomic and structural information of the sample based at least on a comparison of at least two of the holograms of the plurality of holograms.

The invention relates to a method for producing a holographic optical element by providing a recording stack comprising at least one recording element laminated on at least one supporting element, irradiating at least a part of the recording stack with at least one recording beam in an irradiating step, wherein during the irradiating step, the recording stack bends, providing a bending deviation threshold for the recording stack, and adjusting at least one first process parameter such that an expected maximum bending deviation of the recording stack does not exceed the bending deviation threshold, wherein the at least one first process parameter influences the bending behaviour of the recording stack during the irradiating step.

A hologram recording device for producing a hologram that diffracts incident light includes: a laser light source; a first half-wave plate that controls a polarization direction of a light beam emitted from the laser light source; a polarizing beam splitter that reflects S-polarized light to emit the S-polarized light as an A light ray and transmits P-polarized light to emit the P-polarized light as a B light ray with respect to the light beam passing through the first half-wave plate, and splits the light beam in two directions; a first wedge prism mirror that reflects the A light ray; a second half-wave plate that polarizes the B light ray into S-polarized light; a second wedge prism mirror that reflects the S-polarized light polarized by the second half-wave plate; and a recording medium irradiated with light rays reflected by the first wedge prism mirror and the second wedge prism mirror.

A backlight device having a light guide, a first holographic optical element and a second holographic element are provided. The light guide plate guides light emitted by a light source towards the first holographic optical element. The first holographic optical element, which has a multi-layered structure, is provided on a first side of the light guide plate and reflects the light according to the wavelength ranges based on the characteristics of the multi-layered structure. The second holographic optical element, which concentrates light reflected by the first holographic optical element onto at least two points is provided on a second side of the light guide plate perpendicular to the first side.

A backlight device having a light guide, a first holographic optical element and a second holographic element are provided. The light guide plate guides light emitted by a light source towards the first holographic optical element. The first holographic optical element, which has a multi-layered structure, is provided on a first side of the light guide plate and reflects the light according to the wavelength ranges based on the characteristics of the multi-layered structure. The second holographic optical element, which concentrates light reflected by the first holographic optical element onto at least two points is provided on a second side of the light guide plate perpendicular to the first side.

An apparatus for producing an optically variable film includes a laser configured to emit a beam, a telescoping lens section having a first lens and a second lens spaced apart by a first distance and an interferometer configured to direct the beam toward a workpiece. The laser may be operated at a predetermined power level and the first and second lenses are sized and spaced relative to one another to direct the beam onto the workpiece at about 200-230 dots per inch. The workpiece may include a polyethylene terephthalate (PET) layer configured to be ablated by the beam, forming a microstructure in the surface of the layer. The microstructure may be randomized and used to present non-chroma visual effects.

Provided is a method of manufacturing a full-color holographic optical element in a full-color holographic optical element manufacturing apparatus including a lens and a holographic recording medium located farther away than a focal length of the lens, the method including: allowing a signal beam including a mixture of laser beams having wavelengths of R (Red), G (Green), and B (Blue) to be incident on the lens; and recording a hologram in such a manner that a reference beam including a mixture of laser beams having wavelengths of R, G, and B is allowed to be incident on the holographic recording medium, wherein the holographic recording medium is configured with a single medium.