Re: What are the Quantum Mechanics Apllications?

The examples you give, notably lasers and transistors, are very good ones.

Here's an earlier question I answered concerning how quantum effects make solid-state transistors possible; most solid-state devices never could have been invented without an understanding of the underlying quantum mechanics.

The invention of the laser also depended on quantum mechanics; the inventors needed to know about the discrete (quantum) energy levels of electrons, the quantum rules which governed the allowed transitions between levels, and the fact that certain photons could stimulate emissions of other, identical photons (a purely quantum effect).

Other quantum-inspired inventions have included the electron microscope (where electrons must be thought of as quantum wave packets), LEDs (light emitting diodes), and MRI (magnetic resonance imaging) as used in hospitals.