Self mixing laser interferometry is an interferometric technique dating back to 1978 4, known for its structural simplicity. Kobayashi 5, self mixing interferometry smi represents an interferometric setup very simply with respect to the common ones. Optical proximity sensor based on selfmixing interferometry. Pdf edge filter enhanced selfmixing interferometry researchgate. The reflected light interferes with the light generated inside the laser, and this causes changes in the optical and electrical properties of the laser. Paper ii focuses on arterial pulse shape measurement using the self mixing technique. Selfmixing instrument for simultaneous distance and speed. However, a breakthrough appeared in the midnineties with the introduction of the self mixing interferometer smi, 5 the semiconductor laser version of a hene smi precursor first reported 10 years. Pdf selfmixing interferometry smi represents a simple, robust, and self aligned technique for metrology applications. Specifically, the influence of two important system parameters, i. Jun 19, 2002 self mixing interferometer is used, because it is much simper than the conventional interferometers. Laser diode ld self mixing sm or optical feedback interferometry ofi 1, 2 technique has been an active area of research during the last two decades for distance 3, flow 4, displacement 5, velocity 6, and vibration 79 sensing. Inthiswork, self mixinginterferometrysmiisimplementedinlinetoalaser.
Application of selfmixing interferometry for depth. Analog processing of speckle affected selfmixing interferometric. Because the presented algorithm allows working also for highspeed movements, it was designed a large bandwidth transimpedance ampli. Ultrasonic displacement measurement using selfmixing. Norgia etal absolute distance measurement by self mixing interferometry 1895 fig. Pdf transition analysis for moderate feedback self. This paper presents a novel algorithm for measuring the linewidth enhancement factor of semiconductor lasers and the optical feedback level factor in a semiconductor laser with an external cavity. Unlike displacement measuring interferometers, the interferometric signal is usually processed by extracting the doppler beat frequency through a frequency. Smi has practical advantages compared to standard interferometry, for example smi does not require any optical part external to the laser chip and can be employed in a variety of measurements. Analysis and implementation of a direct phase unwrapping. Michele norgia, member, ieee, guido giuliani, member, ieee, and silvano donati. Multiple selfmixing interferometry algorithm based on phase. The self mixing interferometer smi is based on the feed back effect generated by a light illuminating a remote tar get and returning back into the laser cavity. The depth resolution is intrinsically high, since it is half the wavelength of the interferometer typically.
Self mixing interferometry guido giuliani, member, ieee and michele norgia, student member, ieee abstract we demonstrate an easytoimplement method to determine the linewidth of a laser diode based on the measurement of phase noise in a self mixing interferometer. The threshold current of the solitary laser is approximately 0. Laser self mixing interferometry in the gaussian beam approximation. Osa approach to frequency estimation in selfmixing.
Laser diode selfmixing interferometry for velocity. Selfmixing sm or optical feedback interferometry technique 1 has become an attractive area for the sensing of vibration 2 and biomedical. Introduction self mixing interferometry, also known as optical feedback or injection interferometry, is a promising technique for a variety of measurement applications involving interferometry 1. We establish a new quadrature detection system for self mixing interferometry using two photodiodes and a 22. Self mixing interferometry self mixing interferometry has been an active area of research since the early 1980s. Osa quadrature detection for selfmixing interferometry. Overview of self mixing interferometer applications to mechanical engineering silvano donati a and michele norgia b, a university of pavia, department of industrial and information engineering, pavia, italy b politecnico di milano, department of electronics, informatics and bioengineering, milano, italy abstract. Laser diode self mixing interferometry for velocity measurements alexandra s.
Abstract in order to reconstruct the microvibration quickly and easily, a novel phase unwrapping algorithm based on multiple hilbert transform is proposed. The method is based on a rotating beam splitter placed between the laser diode and the measured object, and two quadrature self mixing signals can be obtained. A novel algorithm based on a phase modulation and demodulation technique for multiple self mixing interferometry was proposed in this paper. Multiple selfmixing interferometry algorithm based on. Detection of selfmixing interferometric fringes of a. Whereas for selfmixing interferometry, the depth measurement was based on manual fringe counting after a lowpass digital filtering stage cutoff frequency of 50. We analyze the laser self mixing process in the gaussian beam. The phenomenon was rst characterized by lang and kobayashi 16, who analysed the e ects of external optical feedback in a laser diode ld by means of the delayed di erential equations of involved electric eld. As the readout, we use the self mixing interference in the laser diode due to light scattered by the red cells, whose doppler shifted components comes from the intrinsic divergence of the. Vibration measurement based on multiple hilbert transform. Alexandrova, a,b, vasilis tzoganis, a,b,c and carsten p. The self mixing effect produces a series of interferometric fringes easily detectable with the builtin monitor photodiode. Selfmixing interferometry for rotational speed measurement of servo.
The optical scheme presented uses the photodiode on the back face of a commercial super luminescent diode to detect the interference signal. Selfmixing interferometry in verticalcavity surface. Effect of dualchannel optical feedback on selfmixing. Giles davies, c blake ferguson, d graeme walker, d helmut schaider, e and h. It is demonstrated in the paper that solidstate lasers ssl have smaller linewidth.
Self mixing as a new configuration of interferometer compared to other schemes of interferometry, self mixing yields a different output signal yet information contained in it is the same, a sinecosine function of optical phase length 2ks. Welsch a,b a cockcroft institute, daresbury laboratory, scitech daresbury, daresbury, warrington wa4 4ad, united kingdom. As opposed to conventional interferometry, major advantage. New absolute distance measurement technique with a selfmixing interferometer. Selfmixing interferometry is a measurement technique, in which a laser beam is reflected from an object, back into the laser. Thz qcl selfmixing interferometry for biomedical applications.
Applying music to smi range finding, we find its signal. Pdf self mixing interferometry smi represents a simple, robust, and self aligned technique for metrology applications. In comparison with the traditional ldv, self mixing interferometry smi simply consists of a laser diode, a focusing lens, a target for test, and related electronics for extracting the self mixing signals without any additional orcomplicatedopticalcomponents. Fringe disappearance in selfmixing interferometry laser. Overview of selfmixing interferometer applications to mechanical. Impact of high coupling factor in absolute distance.
We describe a novel layout for the measurement of the extracorporeal blood flow, performed by means of a laser diode placed directly in front of the blood vessel, without the need for any optical element. Nanometerscale displacement sensing using selfmixing. Pdf transition analysis for moderate feedback selfmixing. Mixing lsm interferometry, which does not require any reference arms or external detectors and it is conveniently replicable because of a robust and almost self. Pdf on the feasibility of selfmixing interferometer sensing for. Sensors under the self mixing technique use the laser itself as both the light source and the detector. Many optical elements like the beamsplitter, reference mirror, and external photodetector are not required. It can be observed that the ablation emission is concentrated in visible and uv range, while in the ir region the contribution is not present. A selfmixing interferometer is proposed to measure nanometrescale optical path length changes in the interferometers external cavity. Selfmixing interferometry and its applications core. This algorithm can measure nanoscale vibration in real time and enhance the measurement resolution of a multiple self mixing interferometer twofold compared with that of a self mixing interferometer.
Information about the target object and the laser itself can be obtained by analysing these changes in behaviour. Realtime selfmixing interferometer for long distances. Welsch a,b a cockcroft institute, daresbury laboratory, scitech daresbury, daresbury, warrington wa4 4ad, united kingdom b university of liverpool, department of physics, liverpool l69 7ze, united kingdom criken nishina centre, hirosawa 21, wako, saitama. Real time displacement sensor based on selfmixing interferometry.
For the proposed application, this is not a problem, because we are looking at. Laser diode selfmixing interferometry for velocity measurements. Selfmixing interferometry for biomedical signals sensing. Then, an arctangent phase algorithm can be used to demodulate the quadrature signal to. Figure 3 shows an example of emission spectrum during tin ablation. Pdf optical sensing offers an attractive option for detection of surface biopotentials in human subjects where electromagnetically noisy. Selfmixing lowcoherence interferometry 1998 rovati. Introduction laser feedback interference, also called the laser self mixing effect, has drawn widespread interest in the metrology research community for its advantages, such as compactness, self align. Probing multipulse laser ablation by means of selfmixing. Confocal flowmeter based on selfmixing interferometry for.
Pdf laserselfmixing interferometry in the gaussian. Selfmixing interferometer for contactless vibration. Front and rear outputs are observed to be in phase for the hene laser while they are in phase opposition in the diode. Evaluation of selfmixing interferometry performance in. Selfmixing laser diode vibrometer guido giuliani, simone bozzipietra and silvano donatiapplications of diode laser feedback interferometry silvano donati and sabina merloanalysis for the selfmixing interference effects in a laser diode at high opticalfeedback levels yanguang yu, huiying ye and jianquan yaorecent citations. The emerging optical sensors by laser self mixing sm interferometry incursion in metrological. Still, its applicability on diffuse targets is limited to distances up to few. Introductionin laser diode ld self mixing interferometry, the sawtooth like self mixing signal carries important information which can be used to estimate the metrological parameters of a moving target as well as those of the laser itself. Influence of linewidth enhancement factor \\alpha \ on self. Sinusoidal phasemodulating selfmixing interferometer with. An innovative approach is represented by laser self.
New absolute distance measurement technique with a selfmixing. Sinusoidal phasemodulating selfmixing interferometer. A plain laser diode can easily measure submicron vibrations from centimeters away by self mixing interferometry. A new method for the acquisition of arterial pulse wave. Laser diode selfmixing technique for sensing applications. Detection of selfmixing interferometric fringes of a laser. Self mixing or backinjection laser interferometry is an interferometric technique in which a part of the light reflected by a vibrating target is reflected into the laser cavity, causing a modulation both in amplitude and in frequency of the emitted optical beam. Overview of selfmixing interferometer applications to.
A selfmixing interferometrybased micro flow cytometry system. Absolute distance measurement based on multiple self. Selfmixing interferometry for rotational speed measurement. This paper presents the calculation of amplitude and relative phase of signals at the three outputs available in a self mixing interferometer, i. In this work self mixing interferometry smi is implemented inline to a laser.
The photodiode is encapsulated inside the laser diode module. An analytical method for estimation of parameters of self. Peter soyer e a school of information technology and electrical engineering. Vibration measurement based on multiple selfmixing. In this paper, we demonstrated an improved laser self mixing grating interferometer smgi with autocollimation design which can avoid the disturbance from the light feedback of the zeroorder.
When a portion of the laser output light is reflected or scattered by the vibrating target and returned to the laser cavity. Optimisation of a selfmixing laser displacement sensor oatao. Up to now, laser self mixing interferometry smi has been widely applied to numerous scientific and industry fields. Absolute anglemeasurement with a dihedral mirror of the. The proposed approach is based on analysis of the self mixing phase equation to deduce equations for finding parameters given only knowledge of the perturbed phase. This thesis describes the laser doppler technique based on a self mixing effect in a diode laser to noninvasive cardiovascular pulse. Laser self mixing interferometry smi phenomenon, which was observed in the 1960s, was regarded as a detrimental factor to laser systems at the early stage and has been gradually transformed into a sensing technique since the 1980s. Mixing interferometry for mechatronics applications. A new method for the acquisition of arterial pulse wave using. Probing multipulse laser ablation by means of self mixing. Paper open access highsensitivity vibrometer based on. Jun 17, 2020 please use one of the following formats to cite this article in your essay, paper or report.
For the proposed application, this is not a problem, because we are looking at the target presence, not at its speed or distance. The self mixing interferometry laser should also possess sufficient depth of focus or, namely, rayleigh range. Absolute distance measurement with improved accuracy. Pdf a lensless selfmixing bloodflow sensor semantic scholar. Abstract selfmixing sm or optical feedback interferometry has been extensively used for high precision displacement and vibration sensing. Donati 4 and established for laser diode in 1980 by r. We present an overview of the applications of self mixing interferometer smi. Pdf thickness measurement of transparent plates by a self. The phasedemodulation process is carried out completely in the frequency domain, which is able to effectively improve the dynamic resolution to about 10 nm. Hilbert transform is performed once and three times for self mixing fringes on different inclined directions, then the unwrapped phase is obtained and the microvibration can be reconstructed under weak or even moderate feedback. Then, an arctangent phase algorithm can be used to demodulate the quadrature signal to acquire.
Laser laser s s p d p d ex t r n a l in t e r f e r o m e t r y i i 0 c o s2 k i 0 c o s. In this paper a novel lowcoherence interferometer using a self mixing super luminescent diode is described. Self mixing interferometry smi represents a simple, robust, and self aligned technique for metrology applications. We apply this algorithm to two representative smi measurement techniques. In addition, measuring the distance between the laser source and the target based on selfmixing interferometry has been researched almost. Kg, finsing 85464, germany 2institute for electrical drive systems and power electronics, technical university of munich, munich 80333, germany corresponding author.
Self mixing interferometry smi is an efficient technique applied to measure distance, velocity, displacement, and vibration. Within this context, the principle of selfmixing interferometry provides us with a. Advanced optical components is used as the self mixing nonlinear interferometer. Laser diode linewidth measurement by means of selfmixing. Silvano donati, michele norgia, overview of self mixing interferometer applications to mechanical engineering, opt. The variations in the optical output power of the laser diode p caused by this optical feedback can be written as 1. Pdf thickness measurement of transparent plates by a. Based on the nature of self mixing signals, we propose the use of the multiple signal classification music algorithm in place of the fast fourier transform fft for processing signals obtained from self mixing interferometry smi. Selfmixing interferometer for contactless vibration measurements. Due to the reduced number of components required for its setup 2, and the. Selfmixing interferometry for absolute distance measurement laas. The laser diode is the internal cavity with length l.
Rakic1 1 the university of queensland, school of information technology and electrical engineering, queensland. Abstract self mixing sm or optical feedback interferometry has been extensively used for high precision displacement and vibration sensing. Application of selfmixing interferometry for depth monitoring in the. Self mixing interferometry sm effect is observed when the optical beam is backscattered by a remote target into the active laser cavity thus modifying spectral characteristics of the laser diode. Thz qcl self mixing interferometry for biomedical applications aleksandar d. In addition, the relationship between blood pressure, the radial velocity of the arterial wall and the elastic modulus of the arterial wall is derived. A selfmixing interferometry based micro flow cytometry system. However, the self mixing interference signal contains abundant highorder. Vibrometer based on a selfmixing effect interferometer. Self mixing interferometry theory the classic representation of the laser diode cavity under feedback is depicted in fig.
1553 162 1271 415 6 1069 793 749 237 1228 1265 1037 1239 52 988 331 268 323 604 6 47 832 151 1042 1193 402 577 37 607 784 37 100 643 461 254