Introduction

The invention consists of an optical sensor based on the  random laser principle, for the characterization of diffusive materials, such as powders, biological tissues, liquid dispersions and diffusive surfaces. The sensor shows a very low invasivity and an high sensitivity due to the amplification of the diffuse light.

Technical features

The invention consists of a fiber-coupled optical sensor, based on the phenomenon of random laser, that can be used for the characterization of different materials such as diffusive materials, powders, biological tissues, liquid dispersions and diffusive surfaces. With this device it is possible to determine, in a quick and non invasive manner,  the reduced scattering coefficient (the reciprocal of the transport mean free path for the optical radiation) of the sample, by analyzing the spectral emission of the random laser. A high sensitivity is guaranteed by the amplification mechanism provided by stimulated emission of the diffuse light. Local measurements in difficult environments are possible thanks to the  high portability allowed by the optical fiber coupling and to the fact that the device acts as both emitter and receiver.

Possible Applications

• Characterization of diffusive materials;
• In vivo measurements on biological tissue;
• Quality check.

Advantages

• No invasivity;
• High sensitivity;
• Signal amplification due to stimulated emission in the random laser;
• High portability;
• Possibility to a direct measurement of optical properties;
• Easy to use;
• Able to investigate different materials.