Plasma emission has a feature of being composed of many emission peaks, located closely together. For instance in order to resolve the vibro-rotational emission lines of nitrogen molecule; we need a spectrometer with a resolution of less than 0.3nm. To achieve this high resolution, it is recommended to use multichannel spectrometers or multi grating spectrometers. In the multichannel spectrometer, along with using high groove/mm gratings, the desired wavelength range (for example 200-600nm) is divided to few sections and each section is imaged on a single detector. Therefore, we will be able to measure whole wavelength range with high resolution. In a multi-grating monochromators, the wavelength range and resolution is selected by choosing one of the pre-installed gratings which essentially define the measureable wavelength range. We also suggest a new type of spectrometers features with variable entrance slit. For more information, please look to our spectrometer products.
Typical Setup for Plasma Spectroscopy A typical setup for optical emission spectroscopy can consist of an optical fiber probe and a high sensitivity spectrometer with a proper resolution. The emitted light is collected by a fiber probe and sent to the spectrometer. Figure-3 shows a typical setup for plasma measurement performed on a typical radio frequency (RF)-enhanced chemical vapor deposition. One electrode is connected to an RF voltage source, and the other is grounded. On the introduction of argon, the high voltage causes plasma to form. With carbon-rich gases such as methane, butane, or acetylene, the plasma process decomposes the gas and accelerates the carbon atoms toward the substrate to form the diamond-like carbon (DLC) layer.