Skip to main content

Mode Locking

Mode Locking

Mode Locking Lasers can be made to operate continuously or in pulses. As an example, the bandwidth of the 632.8 nm line in the He-Ne laser is 1.5 GHz, so that the shortest pulses that a He-Ne can produce would be 0.67. ns long. This is not particularly short by modem standards. Dye lasers typically have gain bandwidths greater than 10*1000000000000 Hz and can be used to generate pulses shorter than 100 fs. This is achieved by a technique called mode-locking. To achieve shorter laser pulses, mode locking of the laser modes is done

Mode Locking

Types of Mode Locking

In a comparison of ultrafast and normal lasers, an ultrafast laser simultaneously lases in many different modes (the more the better), but the phases of the different modes are completely uncorrected.


This will manufacture random (unpredictable) Fluctuations within the intensity over time. Mode locking describes the set of techniques that are used to generate a known correlation between the phases and therefore create it possible to predict once the intensity maxima can occur.

Active Mode Locking

A physical device is placed in the cavity, which modulates the frequencies of the cavity modes. It depends on an external source to incite oscillation in the resonant cavity, creating modulated light.


Passive Mode Locking

An intensity dependent loss-mechanism (saturable absorber) placed in the cavity causes less intense radiation to be damped out, leaving only a single, intense pulse oscillating back and forth in the cavity.


Self Mode-Locking

It is a special kind of passive mode locking in which the lasing medium itself has an intensity dependent index of refraction.


Read More

WHAT IS SEMICONDUCTOR

TRAPPED CHARGE EFFECT

Popular posts from this blog

RS Aggarwal Aptitude Book PDF Free Download

RS Aggarwal Aptitude Book PDF Free Download RS Agarwal Aptitude Book PDF Free Download: Quantitative Aptitude by R.S Aggarwal is a standout amongst the most inclining books among the hopefuls getting ready for Bank PO, PO, MBA, RBI, IBPS, CAT, SSC, IAS, PSC, Hotel Management, Railway Recruitment Exams, and other aggressive and placement tests. This book is suggested by different specialists in this field. This book covers relatively every theme which is being requested for the focused exams. On the off chance that you are looking to Download RS Aggarwal Quantitative Aptitude PDF's most recent version with the expectation of complimentary then you appear to be at the correct place.    Download PDF  RS Agarwal Aptitude Book PDF Free Download This book covers Problems on Surds and Indices, Simplification, Numbers and Ages, Pipes and Cisterns, Boats and Streams, Problems on Trains, Simple and Compound Interests, Time and Work, Permutations and Combination, Clocks, Odd Man Out, Heights

Limitations of Terzaghi Theory

Limitations of Terzaghi Theory The value of the coefficient of consolidation has been assumed to be constant.  The distance d of the drainage path cannot be measured accurately in the field. The thickness of the deposit is generally variable, and an average value has to be estimated.  There is sometimes difficulty 1n locating the drainage face, and sometimes thin previous seams that can act as good drainage faces are missed in the boring operations. The equation is based on the assumption that the consolidation is one-dimensional. In the field, the consolidation is generally 3-dimensional. The lateral drainage may have a significant effect on the time rate of consolidation. The initial consolidation and secondary consolidation have been neglected. Sometimes these form an important part of the total consolidation. In actual practice, the pressure distribution may be far from linear or uniform.

Types Of Current Collector

Current Collector A current collector is a device used to collect electrical current from a moving conductor, such as a train or a trolley. It is typically used in electric vehicles, such as trains and trams, to transfer power from an overhead power source to the vehicle's electric motor. The current collector consists of a sliding contact, which is often made of carbon or copper, that makes contact with an overhead power source, such as an overhead catenary wire or a third rail. The sliding contact is mounted on the vehicle and is typically in the form of a pantograph or a trolley pole. The pantograph is a device with a metal frame and a spring-loaded arm that presses against the overhead power source. It is raised and lowered by the operator of the vehicle, and as it moves along the overhead power source it maintains contact and collects the electrical current. The trolley pole is a vertical pole that is mounted on the roof of the vehicle and has a horizontal arm that extends out