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I have been using 785 nm continuous laser for 20 months. 350 mW is the maximum output of the laser mentioned by the manufacturer. At the beginning I used to get the same power with my power meter. However, I can see the power is 285 mW, which means 20% dropped from the maximum power. Is there any suggestions why the power is dropping? any thumbs of rules that can predict the laser life time ?

Good afternoon,... I am frabicating optical grating by micro-contact printing. When I evaluate the treansmission grating with a laser I realize that the 0 and 2nd order of difraction both have higher intensity than the 1st order of difraction..... Please, does any one can suggest me why it could happen?,.. since the 2nd order should have lower intensity than 1st one.

Regards

Daniel

Hi, I'm wondering how I can calculate the fluence of a laser from given parameters . like we have femtosecond laser with Bessel Beam .

1-160Mirowatt Power on power meter

2-10 Hz frequency

3-Beam spot diameter is unknown

4-50x with 0.6NA optical lens

According to the equation Fluence will calculate by F=E/A. But i am confused about Total power ,power on power meter ,pulse energy , laser spot diameter and the A in given equation. Is there any way to calculate the (fluence) of this laser from the mentioned parameters? what's the mathematical relation between given parameters

I would be truly grateful if anyone could answer me.

difference between linear and nonlinear optical properties?

I am trying to calculate the guided modes in a rectangular slab wave-guide which has a refractive index with a quasi Gaussian profile at the slab to clad interface. I am actually working with Lumerical Mode SW and failed to find the way to do it. Any advise will be welcome.

Ori

I'm researching light sources and their UV emissions. I'm curious if a 50W, 7500K conventional LED lamp emits any UV light. I found that a 200W tungsten lamp can emit up to 1.5 mW/cm² at 350 nm. Does anyone have data or experience on UV emissions from high-power LED lamps? Specifically, I'm looking for information on UV intensity and wavelength range for such LEDs. Additionally, if anyone has insights on how to characterize these lamps, that would be greatly appreciated.

Do we really need a femtosecond laser for Laser-induced graphene(LIG) production on polymers?

Other than better resolution and lesser thermal damage is there any other advantages?

Comment:

This comment is on Extended Classical Mechanics (ECM) and massless objects! It proposes some really interesting ideas about anti-gravitational forces and energy exchange mechanisms for massless particles, going beyond conventional understandings of inertia and speed limits. The connection to Planck scales is particularly intriguing. It suggests a need for a revised understanding of how gravity interacts with objects at the quantum level.

Author: Soumendra Nath Thakur

Date: February 18, 2925

Abstract:

This paper explores the behaviour of massless objects within the framework of Extended Classical Mechanics (ECM), proposing that these objects exhibit anti-gravitational forces due to their negative effective mass.

Key Concepts:

1. Massless Objects and Anti-Gravitational Force:

- Massless objects possess an inherent anti-gravitational force against surrounding gravitational influences.

- This phenomenon is attributed to their negative apparent mass (-Mᵃᵖᵖ) and negative effective mass (Mᵉᶠᶠ < 0).

2. Energy Expenditure and Interaction:

- While interacting with gravitational fields, massless objects expend energy, which is not derived from their inherent energy.

- They gain energy through gravitational interactions with massive bodies, retaining this energy upon escaping gravitational fields.

3. Motion Dynamics:

- The motion of massless objects is influenced by their negative apparent mass, leading to continuous motion rather than inertia.

- The speed of these objects is constrained by Planck scales, specifically the ratio of Planck length to Planck time.

4. Wavelength and Speed Limit:

- If the wavelength of a massless object exceeds the minimum Planck length, its speed may surpass conventional limits, resulting in strong anti-gravitational forces.

- This introduces a new perspective on the speed limits of massless bodies.

5. Gravitational Interactions at Quantum Scales:

- At scales smaller than the Planck length, gravitational interactions and energy transformations behave differently, becoming imperceptible under traditional observation methods.

- The principle of energy conservation implies that energy does not vanish but transforms into higher, undetectable energy states.

Conclusion:

The ECM framework challenges conventional mechanics by providing new insights into the motion, gravity, and energy transformation of massless objects. It opens avenues for further research into the fundamental nature of gravity and motion beyond the Planck scale.