Introduction I came across various articles while reading about Spectroscopic Instruments. I revised the work of several scholarly articles about spectroscopy. My goal in this paper is to discuss signal-to-noise ratio and detection limit in terms of spectroscopic instruments. I will do this by comparing and contrasting various devices. I will state the names of the most effective devices. I will also give a summary of their applications. To achieve my goal, I have organized my paper into five main sections and a conclusion. In the first section, I give an introduction to the topic. In the second section, I give a brief background of noise and signals in spectroscopic instruments. In the third section, I provide a summary of the signal-to-noise ratio. In the fourth section, I define Detection Limit. In the fifth section, I explain the process of noise reduction. I end my paper with a conclusion, outlining the best devices used for spectroscopic measurement. Spectroscopy is the measurement of electromagnetic radiation. Atoms and molecules are capable of absorbing and emitting various forms of energy. Energy is measured according to its level of transmission. Energy levels can therefore be compared based on their mode of transmission (Crowe 17). Electromagnetic can be absorbed (Jacobs 19). Electromagnetic energy can be emitted from one level to another (Jacobs 20). Spectroscopic instruments are tools that are used to study the emission and absorption of radiation (Dereniak 16). Light and radiation can be absorbed depending on their specific wavelengths. Spectroscopy is the study of compounds in relation to the radiant energy that is emitted or absorbed at different wavelengths. Types of Signals and Noise “There are three types of noise in the field of spectroscopy: flicker, photon and detector noise” (Froehlich 31). Photon noise is evident in photomultiplier detectors. It disrupts the signals that are read by the machine. Photon noise is proportional to the square root of light intensity (Froehlich 31). The Signal to Noise ratio, therefore, shares a direct proportionality with the breadth of the slit (Basset 47). Detector noise is evident in machines that use solid-state photodiode detectors. As a result, Detector noise is not affected by light intensity. Its Signal Noise ratio shares a direct proportionality with the intensity of the light (Jacobs 24). “Detector Signal to Noise ratio is proportional to the square of the slit width” (Dereniak 47). Flicker noise is caused by suspended particles that scatter the wavelength of light (Basset 127). The incorrect positioning of spectroscopes also causes Flicker noise. Flicker noise may be evident if a source of light is unstable during an experiment. “Flicker noise is directly proportional to the intensity of light” (Jacobs 14). The Flicker Signal to Noise ratio can be adjusted using wavelength modulation and double beams. Signal to Noise Ratio “The quality of a signal is determined by the Signal to Noise ratio. The Signal to Noise ratio is inversely proportional to the relative standard deviation of the signal amplitude” (Crowe 24). If the level of the signal is high, then the noise may also be loud. The interference from flicker and photon noise also depends on the lev