Laser Beams Deflected Off of Nothing but Air for First Time Ever in Breakthrough Patent Pending Process - The Debrief::An international team of scientists report that they have successfully used acoustics to deflect laser beams in an engineering first.

  • Subverb@lemmy.worldEnglish
    901·
    1 year ago

    140 decibels. I’m sure some applications exist but it won’t be a 3D TV soon.

    • Slowy@lemmy.worldEnglish
      492·
      1 year ago

      In an ultrasonic frequency we can’t hear. But your pets and any nearby bats or rodents etc may be upset by it…

        • Slowy@lemmy.worldEnglish
          69·
          1 year ago

          I didn’t know the answer to this so I looked it up - yes. Over 120 Db can cause damage even if it’s ultrasonic and you can’t hear it. Apparently at 155Db the heat created by the sound wave can be dangerous as well.

          • Kazumara@feddit.deEnglish
            40·
            1 year ago

            Just a small note, it’s written dB, small “d”, big “B”.

            “B” is the unit symbol for bel and “d” is the symbol for the SI prefix deci, a tenth.

              • Kazumara@feddit.deEnglish
                3·
                1 year ago

                Oh yes, sure you can, 140 dB is 0.000014 MB. The confusing thing is just that the non-SI unit byte also uses the symbol “B” and uses the SI prefix “M” quite often.

                Sometimes when I calculate optical power levels I actually use B in between. For example:

                How much signal is 88 optical channels at 1.6 dBm of power each?

                0 dBm = 1 mW by definition

                1.6 dB = 0.16 B = log10 ( x ) --> x = 10 ^ 0.16 = 1.45

                So 1.6 dBm is 1.45 * 1 mW = 1.45 mW

                Then 88 channels is 88 * 1.45 mW = 127.60 mW = 127.60 * 1 mW

                log10(127.60) = 2.11 B = 21.1 dB

                So 127.20 mW is 21.1 dBm, just below the output specification of our amplifier, good, nothing should melt.

        • Hamartiogonic@sopuli.xyzEnglish
          16·
          1 year ago

          Yes. Industrial grade ultrasonic sensors are harmful to your health. They can be used, for example, to measure the water level in a tank. If you need to enter a place like that, you should physically disconnect the sensor first. You might not hear much of the noise, but you may feel it in your teeth or some other places.