# F. J. Duarte

All the indistinguishable photons illuminate the array of N slits, or grating, simultaneously. If only one photon propagates, at any given time, then that individual photon illuminates the whole array of N slits simultaneously.

Francisco Javier "Frank" Duarte (born 1 September 1954) is a Chilean-American laser physicist and author who has contributed widely to dye lasers, tunable lasers, multiple-prism optics, and quantum interferometry.

## Quotes

• The two photons are entangled and according to local realism, their polarization planes should become independent... a typical EPR situation. Already in 1948, observations... agreed with quantum mechanics, not with local realism.
• Regardless of the prophetic value of Dirac’s description [on interference] his was probably the first discussion... including a coherent beam of light. In other words, Dirac wrote the first chapter in laser optics.
• in Introduction to Lasers, F. J. Duarte (2003). Tunable Laser Optics. Elsevier Academic. p. 3. ISBN 0-12-222696-8.
• Feynman uses Dirac's notation to describe the quantum mechanics of stimulated emission... he applies that physics to... dye molecules... In this regard, Feynman could have predicted the existence of the tunable laser.
• in Introduction to Lasers, F. J. Duarte (2003). Tunable Laser Optics. Elsevier Academic. p. 3. ISBN 0-12-222696-8.  (while discussing The Feynman Lectures on Physics).
• The Dirac notation, though originally applied to the propagation of single particles, also applies to describing the propagation of ensembles of coherent, or indistinguishable, photons.
• in Dirac Optics, F. J. Duarte (2003). Tunable Laser Optics. Elsevier Academic. p. 25. ISBN 0-12-222696-8.
• All the indistinguishable photons illuminate the array of N slits, or grating, simultaneously. If only one photon propagates, at any given time, then that individual photon illuminates the whole array of N slits simultaneously.
• in Dirac Optics, F. J. Duarte (2003). Tunable Laser Optics. Elsevier Academic. p. 26. ISBN 0-12-222696-8.
• The intimate relation between interference and diffraction has its origin in the interference equation itself.
• in Dirac Optics, F. J. Duarte (2003). Tunable Laser Optics. Elsevier Academic. p. 37. ISBN 0-12-222696-8.
Dirac wrote the first chapter in laser optics.
The intimate relation between interference and diffraction has its origin in the interference equation itself.
I find the concept of a final theory, or a theory of everything, rather limiting.
• Multiple-prism arrays were first introduced by Newton (1704) in his book Opticks. In that visionary volume Newton reported on arrays of nearly isosceles prisms in additive and compensating configurations to control the propagation path and the dispersion of light. Further, he also illustrated slight beam expansion in a single isosceles prism.
• in The Physics of Multiple-Prism Optics, F. J. Duarte (2003). Tunable Laser Optics. Elsevier Academic. p. 57. ISBN 0-12-222696-8.
• The longer the cavity and the narrower the beam waist, the better the beam quality of the laser emission, or
${\displaystyle |\langle x|s\rangle |^{2}\ =\sum _{j=1}^{\mathbb {N} }\,\Psi (r_{j})^{2}\ +2\sum _{j=1}^{\mathbb {N} }\,\Psi (r_{j}){\bigg (}\sum _{m=j+1}^{\mathbb {N} }\,\Psi (r_{m})cos(\Omega _{m}-\Omega _{j}){\bigg )}}$
• in Pulsed Narrow-Linewidth Tunable Laser Oscillators, F. J. Duarte (2003). Tunable Laser Optics. Elsevier Academic. p. 147. ISBN 0-12-222696-8.
• Personally, I find the concept of a "final theory," or a "theory of everything," rather limiting. The fun of discovery will most likely last as long as the human race continues.
• The EPR claim of an "all values" spread in the coordinate depends on an idealized absolute and exact measurement of ${\displaystyle p}$ with ${\displaystyle \Delta p\ =0}$. Since this is physically impossible, the claim of "no physical reality" can be negated.
• The most efficient and practical interpretation of quantum mechanics is... no interpretation at all.