Resistant optical spectroscopic probe

Disclosed is a spectroscopic probe apparatus useful for Raman, near infrared, luminescence, ultraviolet or visible spectroscopies that is formed with a robust method of construction using a molten metal soldering technique. The disclosed method and apparatus provides an optical probe that is easy to manufacture yet able to withstand drastic environmental conditions without damage and produce useful spectroscopic results under such conditions. In a preferred embodiment of the present invention, optical probe (100) comprises a housing (101), closed at one end by tip (102). Two optical fibers (103 and 104), one serving as an excitation channel for radiation from a source to a composition to be analyzed, the other comprising a collection channel for transmitting radiation from the irradiated composition to remotely situated detector means, extend from the terminal surface (105) of the tip through the length of the housing. On the terminal surface (105) of tip (102) is formed a cavity (106), which is filled with molten metal solder that solidifies on cooling to a solder plug. This plug comprises means for securing and sealing the ends of the optical fibre at the terminal surface of the probe tip.