Experimental near infrared absorption enhancement of graphene layers in an optical resonant cavity.

Graphene has recently emerged as a promising candidate for a wide range of photonic and optoelectronic applications, with a high application potential in devices using infrared radiation. The optical absorption of 2D materials and graphene can be uniquely enhanced when they are embedded in optical resonant cavities, since optically-thin atomic-thickness absorbers do not perturb the cavity itself. Despite the many theoretical studies, experimental validation is still lagging behind.

High-precision measurement of optical constants of ultra-thin coating using surface plasmon resonance spectroscopic ellipsometry in Otto-Bliokh configuration.

In this paper, a surface plasmon resonance (SPR) spectroscopic ellipsometry, based on Otto-Bliokh configuration, is developed for the measurement of thickness and optical constants of ultra-thin coatings. This technique combines sensitivity of surface plasmon with accessibility of optical constants and other advantages of ellipsometry. Surface plasmons (SP) are generated in the sample under test in total reflectance mode and SP geometric distribution over the sample surface is influenced by the coating thickness and optical properties on one hand, and by the air gap thickness on the other hand.

Behavior of optical thin-film materials and coatings under proton and gamma irradiation.

Optical materials and coatings are exposed to the flux of energetic particles when used in either space applications or nuclear energy plants. The study of their behavior in such an environment is important to avoid failure of the optical components during their operation. The optical performance of several thin-film materials ((HfO2, Ta2O5, Nb2O5, TiO2, SiO2) and coatings, under irradiation with high-dose gamma rays (5.

Optical transmission filters for observation of lightning phenomena in the Earth atmosphere.

Very narrowband transmission filters, as parts of an instrument for the study of lightning phenomena, are described. Their performance must be maintained at an incidence angle of ±5.5° and this condition poses some limitations on the minimum bandwidth of the order of a few nanometers.

Variable narrow-band transmission filters for spectrometry from space. 2. Fabrication process.

The optical components described here are variable narrow-band transmission filters, where the transmittance peak varies with the position along the surface of the filter itself. They allow the construction of ultracompact and low-weight spectrometers for space applications. The theoretical behavior of graded filters has been already investigated by the authors, for imaging spectrometry of the Earth surface.

Variable narrowband transmission filters with a wide rejection band for spectrometry.

Variable narrowband transmission filters are useful for the development of compact spectrometers. For this purpose the filter should be directly coupled to the detector and the wavelength of the transmission peak should move in one surface direction over a length of a few millimeters. To obtain both a wide measurement spectrum and high accuracy, the ratio of extreme operating wavelengths is required to be greater than 2:1 and the width of the transmission band narrower than 10 nm.

Multilayer coatings on glass for painting protection and optimized color rendering.

Optical coatings offer a solution to the problem of damage to paintings, caused by ultraviolet and infrared radiation, by cutting radiation wavelengths outside the visible range. Simultaneously, these coatings can enhance an observer's viewing of the paintings by reducing the reflections from ordinary glass panes. All these functions should be performed by the same coating.

[Treatment of pain in chronic calcifying pancreatitis with endoscopy and extracorporeal shock wave lithotripsy. A case report].

Abdominal pain is the most frequent symptom of chronic pancreatitis and may, on occasions, lead to great treatment problems. The case of a 56-years-old patient with idiopathic chronic pancreatitis calcifying who showed intracanalicular lithiasis is reported. Treatment with endoscopy and extracorporal shock wave lithotripsy (ESWL) was successful.

Phase shift of stepwise reflectivity profile mirrors.

The effects of phase shifts in laser beams transmitted by output couplers with a stepwise reflectivity profile have been experimentally investigated with a XeCl laser. It is shown that the phase distortions of the cavity output coupler affect significantly the propagation properties of the output laser beam but do not affect the output beam energy and pulse width.

Coatings with graded-reflectance profile: conventional and unconventional characteristics.

The main feature of graded optical coatings is a spatial reflectance profile that displays a maximum value at the coating center and goes toward a minimum along the radius according to a predefined law. A number of other requirements for using graded coatings in the laser field have been added to this basic property during the course of time. After a survey of the conventional properties of graded coatings, these additional characteristics are described, and their influence on the coating design and performance is examined.

Laser mirrors with variable reflected intensity and uniform phase shift: design process.

Optical coatings with circularly symmetric graded reflectance are used as laser mirrors in unstable resonators. A proper design of such coatings permits any maximum central reflectance to be obtained along with a null external reflectance. Different design approaches are discussed, and an optimized design that gives negligible distortion of the reflected and transmitted wave front is proposed.

Optical coatings with variable reflectance for laser mirrors.

Design procedures and fabrication techniques of variable reflectance dielectric mirrors for laser output couplers are proposed. The design criteria, based on the use of only one shaped layer in a multilayer structure, yield any peak value and shape of the reflectance profile. The deposition technique of the variable thickness layer consists of a sputtering process with a suitable mask interposed between the target and substrate.

All-oxide broadband antireflection coatings by reactive ion plating deposition.

Coating experiments were made with reactive low-voltage ion plating to achieve the computer designed performance of all-oxide broadband antireflection systems on BK-7 glass. Reasonable accordance between calculated design and coating experiment as well as reliable production have been demonstrated.