Consiglio Nazionale Delle Ricerche

Universtà Degli Studi Di Firenze

Università Degli Studi Di Firenze

Agenzia Spaziale Italiana

Paolo De Natale

Pietro Ferraro

Gianluca Gagliardi

Giovanni Giusfredi

Pablo Cancio Pastor

Antonio Giorgini

Saverio Avino

Davide Mazzotti

Pietro Malara

Sergio De Nicola

Iacopo Galli

Mauro Giuntini

Saverio Bartalini

Alessio Montori

Marco De Pas

Inaki Lopez Garcia

Simone Borri

Mario Siciliani De Cumis

Alberto Roncaglia

Mariaconcetta Canino

A method to measure the refractive index of a sample, includes: providing a plasmonic sensor including a sensing surface in contact with the sample; providing an optical resonator, the plasmonic sensor being integrated therein as a reflecting surface; providing a first input field of electromagnetic radiation as a primary carrier; providing a second input field of electromagnetic radiation as a secondary carrier having a second frequency different from the first and defined as: second frequency=first frequency+&#x394;v and having a TE and/or a TM polarized component; impinging simultaneously with the first and second input field the plasmonic sensor; tuning the frequency of the first field and/or the value of &#x394;v; detecting a resonator output power corresponding to the first and second intra-cavity fields resonating; determining a difference between the first and the second resonating frequencies; and calculating the refractive index of the sample from the difference.

Method to measure the refractive index of a sample using surface plasmon polaritons

The present invention is relative to a method of ring-down spectroscopy in saturated-absorption condition, for measuring a first concentration of a gas through a measurement of the spectrum of a molecular transition of said gas.

Method for measuring the concentration of trace gases by SCAR spectroscopy

The present invention relates to a ring-down spectrometry apparatus in absorption saturation condition, for measuring the concentration of a gas through a measurement of the spectrum of a molecular transition of said gas. The apparatus includes a laser source, an adjuster for varying the wavelength of said radiation emitted by said laser, and a resonant cavity. A photodetector is adapted to detect an electromagnetic radiation beam and is adapted to generate a decay signal. An electronic circuit receives the signal from the photodetector and is adapted to convert it to a processor. A processor is adapted to receive said decay signal from the photodetector and perform interpolation to obtain a concentration of said gas.

Apparatus and method for measuring the concentration of trace gases by SCAR spectroscopy

Low-noise current source, configured to be supplied by at least one DC main supply (V) and to deliver an output current (I), the source comprising one or more current generator modules (G, G, . . . G) operating in parallel each one of which is configured to deliver a respective output current (I), whereby the output current (I) of the source is equal to the sum of the output currents (I) of said one or more current generator modules (G, G, . . . G), each current generator module (G; G; . . . G) comprising a regulator component (Q), configured to deliver the output current (I) of the current generator module (G; G; . . . G), a sensing resistor (R) connected in series to the regulator component (Q), and an error amplifier stage (IC), configured to compare a reference voltage (V) with a voltage drop (V) across the sensing resistor (R), whereby the error amplifier stage (IC) is configured to amplify an error signal equal to a difference between the between voltage (V) and voltage across the sensing resistor (R), the error amplifier stage (IC) being configured to output the amplified error signal that is configured to control the regulator component (Q), the current source being characterized in that each current generator module (G; G; . . . G) further comprises a first shunt type regulator (Z, I), configured to be connected to said at least one DC main supply (V), that is further configured to generate a dedicated supply voltage supplying the error amplifier stage (IC), whereby the error amplifier stage (IC) is configured to be supplied in a floating manner with respect to said at least one DC main supply (V).

Low-noise current source including one or more current generator modules

The present invention relates to a method and an apparatus to perform frequency comb spectroscopy. The method includes: &#x2014;Arranging a waveguide optical cavity () having a plurality of cavity mode frequencies with a cavity mode frequency spacing (FSR), said waveguide optical cavity being dispersive so that the frequency spacing of the cavity modes is wavelength dependent; &#x2014;Arranging a sample (S) with respect to the waveguide optical cavity () so that the sample is capable of absorbing light travelling into the waveguide optical cavity; &#x2014;Coupling pulsed light coming from a light source () into the waveguide optical cavity (), the source light including source comb frequencies (OCF) with a source frequency spacing (RR), the coupled light including an interval of frequencies centered on a main frequency of said comb frequencies due to cavity dispersion; &#x2014;Locking the waveguide optical cavity to the frequency comb at said main optical frequency; &#x2014;Detecting transmitted cavity frequencies; &#x2014;Determining absorption by said sample (S) of said main optical frequency from the detected transmitted frequencies, &#x2014;Changing the cavity mode frequency (FSR) spacing or the source frequency spacing (RR); &#x2014;Coupling the pulse light to the waveguide optical cavity (), the coupled light including an interval of frequencies centered on a second main frequency of said comb frequencies due to cavity dispersion; &#x2014;Locking the waveguide optical cavity to the frequency comb at said second main optical frequency; &#x2014;Detecting transmitted cavity frequencies; &#x2014;Determining absorption by said sample of said second main optical frequency from the detected transmitted frequencies.

Frequency comb spectroscopy apparatus and method of frequency comb spectroscopy

Growing community of inventors

Prato, Italy

Paolo De Natale