Jedi's LIGHTSABER in STARWARS Movie

The lightsaber is a fictional weapon that plays a key role in the movie, games and novels that constitute the Starwars universe. Lightsabers are science fiction versions of their namesake, the saber. Instead of a metal blade, the lightsaber holds a retractable, brightly colored "energy blade" about one meter in length. Though they often behave like regular sword, they are also depicted as able to cut through most matter with little or no resistance and to deflect projectiles and other weapons in the Star Wars universe. The lightsaber first appeared in the film Starwars IV: New Hope (1977). Rotoscoping was used to create the lightsaber's distinct appearance in the original trilogy. For the prequel trilogy, the effect was created using computer animation.

Within the fiction of Star Wars, the lightsaber "blade" consists of a very tight loop of highly focused energy, or a loop of plasma contained in a strong magnetic or other field. When deactivated, a lightsaber appears as a polished metallic handle, about 30 centimeters long. Lightsabers emit a distinctive hum when active, which rises in pitch and volume as the blade is moved rapidly through the air. A loud crackling noise is heard when two lightsaber blades come into contact.

Designed as much for elegance in combat as for ceremony, the lightsaber was a distinctive weapon, the very image of which was inextricably bound with the mythos of the Jedi and the Sith.
It was a blade of pure energy emitted from a hilt most often crafted by the wielder to match their own needs, preferences, and style. Because of the unique balance of the saber, with all its weight in the hilt, and a strong gyroscopic effect it was very difficult for the untrained to wield. In the hands of an expert in tune with the Force, such as the Jedi or their fallen brethren, the Sith, the lightsaber was a weapon to be greatly respected, even feared. To wield a lightsaber was to demonstrate incredible skill and confidence, as well as masterful dexterity and attunement to the Force.
Through the millennia of their use, the lightsaber became synonymous with the Jedi and their values to uphold peace and justice throughout the galaxy. This perception endured despite the many early conflicts with Sith and Dark Jedi who also wielded what the general populace often called laser swords.
The ritual of constructing one's own lightsaber was an integral part of Jedi training, and involved not just technological skill, but also a close attunement to the Force. In the days of the Old Republic, the ice caverns of Ilum were used as a ceremonial site where Padawans came to build their first sabers. It was here and similar places like the caves near the Jedi Enclave on Dantooine that the Jedi would choose the best focusing crystal for them through meditation and communion with the Force, and then complete the assembly of their lightsaber.
Traditionally, constructing a lightsaber took about a month. This includes assembling the pieces, both by hand and with the Force, and meditating to imbue the crystals. A Jedi would often spend weeks putting it together, making sure that each part fit perfectly, and that it met their exact preferences in length, color, blade frequency, and so on; at the height of the Clone Wars, though, it was reported that one could be built in as little as two days. Corran Horn's first lightsaber, a dual-phase lightsaber constructed during his time under cover as an Invid pirate, is an example of one made in such a timeframe.

The lightsaber's hilt consisted of an alloy cylinder traditionally 25 to 30 centimeters long; however, design and dimensions of hilts varied greatly in part to the preferences and physiological needs of each creator. The hilt casing contained the intricate components that created and shaped the unique blade. High-powered energy was unleashed through a series of positively charged focusing lenses and energizers, manifesting a beam of energy that extended outward from the base to a length of about a meter, then arced circumferentially back to a negatively charged fissure ringing the emitter. A superconductor completed the power loop by feeding the transformed energy back into the internal power cell, where the energy loop began anew. By adding up to three focusing crystals of varying attributes, the blade's length and power output could be adjusted using control mechanisms built into the hilt's shaft.
Two crystals employing a bifurcating cyclical-ignition pulse would allow the blade to be used underwater, but this modification added difficulty to what was an already complicated construction process. As a result, most lightsabers did not include 'waterproofing', and would short out when submerged in water. Rain, however, was vaporized on contact. Generally only Jedi from aquatic races such as Kit Fisto, would go to the trouble of constructing a waterproof saber, as only they had the mobility to use it effectively underwater.
Whether by the fledgling Padawan or the experienced master, construction of the lightsaber began with the acquisition of the necessary components with which to build the weapon. All lightsabers contain some common basic components:

A cutaway of Anakin Skywalker's lightsaber from A New Hope.
A handgrip
An activation stud plate
A safety switch
An emitter matrix
A lens assembly
A power cell (for the most part, unlimited in power; requires little recharging)
A power conduit
A recharge socket (recharges the power cell when the lightsaber is off)
One to three focusing crystals
Many lightsabers, such as that wielded by Zayne Carrick in 3,964 BBY, made use of a pressure sensor in the hilt's grip that deactivated the blade whenever it was released. Notably, Dart Maul's double-bladed lightsaber lacked such a security measure. Other lightsabers were constructed either without the pressure sensor or with a locking mechanism to keep the blade activated when thrown or dropped.
Traditionally, the crystal was the last component to be sought. It was the very life essence of the weapon, and gave it both its color and potency. Much scrutiny went into the selection of this final and most important element of the lightsaber.

Padawans learning to build lightsabers under Vodo-Siosk Baas.
With all the components in hand, the Jedi would begin the assembly process. Because of the intricacies of the technology used, the Force was employed to bind the components at a molecular level. This micro-manipulation of the components enabled the closed loop design to operate with near-perfect efficiency.
While many lightsabers appear similar at first glance, closer inspection reveals many differences (subtle or obvious) in design. Because each Jedi personally constructed his or her own weapon from scratch, no two lightsabers were the same. However, some Padawans built their lightsabers to resemble those of their Masters as a sign of respect.
The knowledge of lightsaber construction largely disappeared during the extermination of the Jedi, but Luke Skywalker found the records and the materials he needed to construct his own lightsaber in Obi-Wan Kenobi's hut on Tatooine.
It is also important to note that Wade Vox and Jaden Korr were among the few capable of successfully constructing a lightsaber without any formal Jedi instruction.