For the second article of this series of articles on Raman spectroscopy I will review some of the latest in Raman technology. Raman has become one of the most important technologies. The large number of vendors with Raman spectrometers of different sizes is overwhelming.
In recent years, there has been a dramatic decrease in the size of Raman spectrometers. Numerous companies offer hand-held or highly portable spectrometers. The award for smallest new instrument goes to Snowy Mountain Instruments of Wyoming. This instrument has a cross-sectional area of about ½ of an Iphone. Instruments that are this portable are ideal for material identification in the field by law enforcement officials. This instrument has a special rastering technology that effectively increases the spot size of the Raman measurement, which decreases the likelihood of the laser beam damaging the sample. The Snowy Mountain Instruments Raman spectrometer is shown in Figure one.
Figure 1: Very small Raman spectrometer introduced by Snowy Mountain at Pittcon
The use of near IR lasers for Raman excitation has grown in recent years. NIR lasers excitation helps to reduce the problem of sample fluorescence. A hand-held Raman spectrometer with 1064 nm laser excitation was introduced by BaySpec corporation of California a few years ago. Now marketed by Rigaku Raman Technology of Texas, this hand-held Raman spectrometer has been improved with the addition of a barcode reader. The Rigaku FirstGuard instrument is shown in Figure 2. B&W Tek of Delaware, StellarNet of Florida, and Delta Nu of Wyoming have introduced Raman spectrometer with 1064 and or 1030 nm excitation. The appearance of more vendors with NIR laser based Raman will speed its application and help produce competitive pricing. The subject of NIR laser based Raman spectroscopy will be the topic of another article in the near future.
Figure 2: Hand-held Raman spectrometer with 1064 nm excitation sold by Rigaku Raman Technology.
An important form of Raman spectroscopy is Raman microscopy, where an optical microscope is combined with Raman spectroscopy to make microscopic maps of chemically specific information. Several companies have introduced new Raman microscopes to the market. BaySpec Corporation of California has introduced the Nomadic Raman microscope. The Nomadic can be operated with three different lasers (532, 785, and 1064 nm). A Raman microscope with NIR excitation (1064 nm) is novel, and an important advance. This will expand the number of systems that can be studied using Raman microscopy.
The importance of Raman spectroscopy is demonstrated by interest in Raman spectroscopy from around the globe. EnSpectr is a Russian based company specializing in Raman technology. I met one the principals of the firm last year at a conference in Moscow. I was impressed with the progress that they have made in less than one year. EnSpectr has a portable Raman spectrometer with a 532 nm laser excitation. In addition EnSpectr has released a Raman microscope and a laboratory based system.