We report on a widely tunable continuous-wave single-frequency pump-resonant signal-resonant optical parametric oscillator (PRSRO) delivering 20 mW to 50 mW of idler power spanning an octave bandwidth in the mid-infrared (1.7 µm–3.5 µm). This PRSRO is pumped by a continuous-wave Ti:Al2O3 single-frequency and tunable laser delivering 760 mW around 795 nm, and thanks to the pump enhancement a threshold as low as 110 mW is achieved. This nonlinear laser source which is widely tunable in the mid-IR spectral range is part of the radiometric laser chain project aimed at the calibration of the spectral responsivity of photo-detectors in the UV-IR range by spectral irradiance measurement via a cryogenic radiometer. This widely tunable source is also suited to high-resolution molecular spectroscopy in the mid-infrared range.

This article describes a new technique to interrogate photonic biosensors for applications in the field of health. The first part presents a type of photonic biosensors: a planar, cyclic microresonator in polymer, shaped racetrack, coupled vertically to a straight waveguide used as input and output for the light. In order, to be adapted for biological applications, the sensor is inserted into an optofluidique cell and its surface is functionalized. The second part of the article describes the phase sensitive optical low coherence interferometer of LNE, proposed as a new interrogation technique of this type of biosensors. Originally developed to characterize, from a metrological point of view, fibre’s components used in the field of telecommunications, this Michelson interferometer with a broadband source has been adapted to such applications. Preliminary results in a biological domain highlight the relevance of this technique and of these microresonators for applications in the field of health.

New “large area” trap detectors based on silicon photodiodes of (18 × 18) mm² have been characterized to be used as standards for measuring the spectral responsivity of detectors. The study of these detectors was carried out on the experimental set-up of the laboratory based on a monochromator and sources of continuous spectral radiation. This article describes the developed trap detectors, details the method of measuring their relative spectral responsivity and presents the method used to change the relative spectral responsivity into the absolute spectral responsivity.

The standard NF X 10-702-1 (Determination of the opacity of the fumes in an atmosphere without air renewal) describes a fire test method of materials exposed to irradiance of a furnace, by quantifying the smoke production from material in predefined irradiance exposure conditions. The standard defines the test apparatus and the operations to be carried out in order to ensure the metrological control of test apparatus. In particular, the 2.5 W·cm^-2 irradiance, which a sample is exposed to during a test, must be adjusted using a radiometer. This radiometer is calibrated against a reference calorimeter according to this standard. The aim of this paper is to describe this calibration uncertainty evaluation. It includes the following steps: evaluation of the associated uncertainty of the reference calorimeter, modelling of the calibration regression and determination of the uncertainties on the irradiance for a given output tension of the radiometer. This work allowed to globally improve the quality of calibrations, through the quantification and control of uncertainties, and by supplying complementary data enlarging the calibration range.

By the scanning beam method a large monochromatic and uniform synthetic beam is obtained from the juxtaposition of a same beam at several places close together. Such an irradiance cannot be obtained by a single beam. We report here a improvement of a setup for irradiance responsivity calibration of detector. The special feature of this work is the use of an incoherent monochromatic beam with a non gaussian profile. The method has been qualified by a numerical simulation of the measurement process then validated by comparing the results with a classical method. This setup has been implemented for the irradiance responsivity measurement of a thermopile. Then, despite of the 10% local variation, its responsivity has been measured at 0.35% uncertainty level. The value agrees the previous measurements with an other method of this thermopile over 20 years. Furthermore it shows an uncertainty which is half the previous one. We plan to extend this method to other instruments such as mosaic photometer because of its ability to take into account large local responsivity variations.

This paper presents a low coherence interferometer as a new interrogation technique of micro-resonator for biological molecules sensing. The spatial responses obtained with PS-OLCI setup are used to evaluate relevant parameters of micro-resonator design like coupling coefficient which allows to discern different coupling configurations. This setup, which is able to provide almost simultaneously the transverse magnetic and electric responses was used to evaluate the spectral performances of micro-resonator. The best performances were obtained on a polymeric racetrack micro-resonator when immersed in deionized water. This micro-resonator displays at 1 527.7 nm a Q factor higher than 38 000 and a finesse of 21. The association of the interferometric set-up and a polymer micro-resonator was allowed the detection of the concentration of glucose in deionized water lower than 5 µg·mL^-1 for homogeneous sensing and the surface density of TAMRA Cadaverin lower than 4 ag·mm^-2 for surface sensing.

Nowadays, there are few high level metrological devices able to measure accurately the regular reflectance in the infrared region. The Laboratoire national de métrologie et d’essais (LNE) has developed an apparatus designed for the absolute measurement of this parameter in the infrared using the goniometer technique. This method is well appropriate for the measurement of spectral regular reflectance of materials with flat, non-scattering and high reflectivity surfaces such as mirrors. The apparatus works in a wide part of the infrared region (from 1 µm to 16 µm) and can operate in the visible and near infrared spectrum too. Mirror alignments, detection system and concentricity of opto-mechanics elements were optimized to reach uncertainties going from 0,001 to 0,015 depending on the wavelengths.

Control of sunbeds is mandatory in France to ensure consumers protection against UV radiation. This control is performed by authorized body with array spectroradiometers that must be calibrated and traceable to SI. These spectroradiometers have defects (stray light) that need to be taken into account while performing the calibration. We propose a calibration method that is based on light sources which spectrum is similar to that of the light sources found in sunbeds, and by comparison to a reference spectroradiometer. This paper report on the bench and procedure developed to calibrate the array spectroradiometer as well as the calibration uncertainty.

The French National Metrology Laboratory, the LNE-LCM, uses a cryogenic radiometer as the basis for its optical radiation measurement scales. This instrument is an absolute radiometer operating at 4.2 K based on the electrical substitution method. It allows absolute measurements of the optical power of laser beams with a relative standard uncertainty in the range of 5 parts in 10⁵. A new cryogenic radiometer was installed in the laboratory and the present paper describes its complete metrological characterization which allows to achieve this level of uncertainty.

Spectrophotometers allow measurement of the optical properties of materials such as transmittance or reflectance. They are used in many industrial fields: health, transport, energy. . . To ensure the traceability of the measurements through the calibration of transmittance and reflectance standards, the LNE uses spectrophotometers that are qualified along the lifetime of these instruments. We present the qualification steps. The results are used to evaluate the uncertainties. The procedure followed can be used as a guideline for spectrophotometer users who want to evaluate their measurement uncertainties.