explain what led to the invention of lasers

Answers

Answer 1

Answer:

The laser is an outgrowth of a suggestion made by Albert Einstein in 1916 that under the proper circumstances atoms could release excess energy as light—either spontaneously or when stimulated by light.

Explanation:

The laser is an outgrowth of a suggestion made by Albert Einstein in 1916 that under the proper circumstances atoms could release excess energy as light—either spontaneously or when stimulated by light. German physicist Rudolf Walther Ladenburg first observed stimulated emission in 1928, although at the time it seemed to have no practical use.

In 1951 Charles H. Townes, then at Columbia University in New York City, thought of a way to generate stimulated emission at microwave frequencies. At the end of 1953, he demonstrated a working device that focused “excited” (see below Energy levels and stimulated emissions) ammonia molecules in a resonant microwave cavity, where they emitted a pure microwave frequency. Townes named the device a maser, for “microwave amplification by the stimulated emission of radiation.” Aleksandr Mikhaylovich Prokhorov and Nikolay Gennadiyevich Basov of the P.N. Lebedev Physical Institute in Moscow independently described the theory of maser operation. For their work all three shared the 1964 Nobel Prize for Physics.

An intense burst of maser research followed in the mid-1950s, but masers found only a limited range of applications as low-noise microwave amplifiers and atomic clocks. In 1957 Townes proposed to his brother-in-law and former postdoctoral student at Columbia University, Arthur L. Schawlow (then at Bell Laboratories), that they try to extend maser action to the much shorter wavelengths of infrared or visible light. Townes also had discussions with a graduate student at Columbia University, Gordon Gould, who quickly developed his own laser ideas. Townes and Schawlow published their ideas for an “optical maser” in a seminal paper in the December 15, 1958, issue of Physical Review. Meanwhile, Gould coined the word laser and wrote a patent application. Whether Townes or Gould should be credited as the “inventor” of the laser thus became a matter of intense debate and led to years of litigation. Eventually, Gould received a series of four patents starting in 1977 that earned him millions of dollars in royalties.

The Townes-Schawlow proposal led several groups to try building a laser. The Gould proposal became the basis of a classified military contract. Success came first to Theodore H. Maiman, who took a different approach at Hughes Research Laboratories in Malibu, California. He fired bright pulses from a photographer’s flash lamp to excite chromium atoms in a crystal of synthetic ruby, a material he chose because he had studied carefully how it absorbed and emitted light and calculated that it should work as a laser. On May 16, 1960, he produced red pulses from a ruby rod about the size of a fingertip. In December 1960 Ali Javan, William Bennett, Jr., and Donald Herriott at Bell Labs built the first gas laser, which generated a continuous infrared beam from a mixture of helium and neon. In 1962 Robert N. Hall and coworkers at the General Electric Research and Development Center in Schenectady, New York, made the first semiconductor laser.

While lasers quickly caught the public imagination, perhaps for their similarity to the “heat rays” of science fiction, practical applications took years to develop. A young physicist named Irnee D’Haenens, while working with Maiman on the ruby laser, joked that the device was “a solution looking for a problem,” and the line lingered in the laser community for many years. Townes and Schawlow had expected laser beams to be used in basic research and to send signals through air or space. Gould envisioned more powerful beams capable of cutting and drilling many materials. A key early success came in late 1963 when two researchers at the University of Michigan, Emmett Leith and Juris Upatnieks, used lasers to make the first three-dimensional holograms (see holography).

Helium-neon lasers were the first lasers with broad commercial applications. Because they could be adjusted to generate a visible red beam instead of an infrared beam, they found immediate use projecting straight lines for alignment, surveying, construction, and irrigation. Soon eye surgeons were using pulses from ruby lasers to weld detached retinas back in place without cutting into the eye. The first large-scale application for lasers was the laser scanner for automated checkout in supermarkets, which was developed in the mid-1970s and became common a few years later. Compact disc audio players and laser printers for personal computers soon followed.


Related Questions

Which computers were the first PCs with a GUI
MS-DOS
Linux
Windows
Mac

Answers

Answer:

The first computer with a GUI were linux, microsoft and apple.

Explanation:

I think this is right. Hope it helped <3

Answer:

I think it's "Mac"

Explanation:

Sorry if it was wrong

Let's review. What can be stored in a
variable? Why is using a meaningful
name for the variable important?

Answers

Answer:

In this lesson students work with partners to investigate several versions of the "Thermostat App" to understand how variables store and update information. To begin, students examine a version of the app where the temperature displayed changes each time a button is clicked. The next two versions of the app demonstrate how variables can store strings. Students learn about the patterns they are observing, specifically "Counter Pattern with Event" and "Variables with String Concatenation Pattern". To conclude the lesson, students review and discuss the programming patterns that they will make use of in the programs they write.

Explanation:

basta isagot mo

Create a program that draws a rectangle whenever you click the mouse. The rectangle should have a width of 30 and a height of 50 and be centered at the place where the user clicks. Remember, the position of a rectangle is the top left corner. To place the rectangle at the center of the click, you will need to adjust the position.

Answers

Answer:

RECT_HEIGHT = 50

RECT_WIDTH = 30

rect = Rectangle(50,30)

       

# random.choice returns a random value from the COLORS

# function will draw a rectangle at x, y

def draw_rect(x, y):

   rectangle = Rect(50, 30)

   rect.set_position(x, y)

   rect.set_color(Color.green)

   add(rect)

# Link to the mouse click event

   add_mouse_click_handler(draw_rect)

Explanation: Hope this works for you.

Write a function called min that returns the minimum of the two numbers passed in as parameters.

Note: Be sure to include comments for all functions that you use or create.

For example, if you made a call like

x = min(10, 14)
x should have the value 10.

For your program, you need to define the function and call it and print out the result like this:

x = min(10, 14)
print("The min is " + str(x))

min(1,2);
min(9000,9001);

it is in python

Answers

def min(x,y):

   smallest = x

   if y < smallest:

       smallest = y

   return smallest

x = min(2,1)

print("The min is "+str(x))

Although I wouldn't recommend using the name min for a function because min is the name of an existing function. Best of luck.

The function is an illustration of conditional statements.

Conditional statements are statements whose execution depends on their truth values.

The function in Python, where comments are used to explain each line is as follows:

#This defines the function

def min(num1,num2):

#This initializes minVal

  minVal = num2

#If num1 is less than num2, then

  if num1 < num2:

#minVal equals num1

      minVal = num1

#This returns the smaller value

  return minVal

At the end of the program, the smaller value is returned to the main

Read more about similar programs at:

https://brainly.com/question/6973180

What should a web page designer consider when choosing between fixed positioning and absolute positioning?

Answers

Answer:

The answer is C I think.

Explanation:

What a web page designer should consider when choosing between fixed positioning and absolute positioning is that ;

the web page designer should know if the page can be found easily.

Since fixed positioning is relative to the browser window and  absolute positioning on the other hand  is been placed on specific place on a web page, then the web page designer should know if the page can be found easily.

Therefore, fixed positioning is relative to the browser window.

Learn more about positioning at;

https://brainly.com/question/15683939

i’m failing this class and i’m stuck on this one, this is the code from the last lesson:

def GPAcalc(grade, weighted):
grade = grade.lower()
dictionary = {"a":4, "b":3, "c":2, "d":1, "f":0}
if weighted == 1 and grade in dictionary:
return "Your GPA score is: " + str(dictionary[grade] + 1)
elif weighted == 0 and grade in dictionary:
return "Your GPA score is: " + str(dictionary[grade])
else:
return"Invalid"

print(GPAcalc(input("Enter your Letter Grade: "), int(input("Is it weighted? (1 = yes, 0 = no) "))))

Answers

lst=([])

def avgGPA(lst1):

   total = 0

   count = 0

   for x in lst:

       if type(x) == int:

           total += x

           count += 1

   return total/count

def GPAcalc(grade, weighted):

   grade = grade.lower()

   dictionary = {"a": 4, "b": 3, "c": 2, "d": 1, "f": 0}

   if weighted == 1 and grade in dictionary:

       lst.append(dictionary[grade]+1)

       return "Your GPA score is: " + str(dictionary[grade] + 1)

   elif weighted == 0 and grade in dictionary:

       lst.append(dictionary[grade])

       return "Your GPA score is: " + str(dictionary[grade])

   else:

       lst.append("Invalid")

       return "Invalid"

classes = int(input("How many Classes are you taking? "))

i = 0

while i < classes:

   print(GPAcalc(input("Enter your Letter Grade: "), int(input("Is it weighted? (1 = yes) "))))

   i += 1

print("Your weighted GPA is a "+str(avgGPA(lst)))

If you need me to change any code, I'll do my best. I hope this helps!

Macro photographs are what type of photographs? A. Close-up B. Telephoto C. Abstract D. All of the above

Answers

Answer:

A

Explanation:

they are close up. they are not telephoto or abstract

marco can be telephoto, but it is not nessacarily always telephoto. marco is by definition a close up photo

HELP ME PLSSSS
Why are peripherals added to computers????
15 points!

Answers

A piece of computer hardware that is added to a computer in order to expand its abilities. ... Subsystem that transfers data between computer components inside a computer or between computers. Unlike a point-to-point connection, it can logically connect several peripherals over the same set of wires.

Answer:

Expand their capabilities

Explanation:

what is the output of this program ? Assume the user enters 3,6 and 11​

Answers

Answer:

C++

Explanation:

C++ Standards

C++ is standardized as ISO/IEC 14882. Currently, there are two versions:

C++98 (ISO/IEC 14882:1998): First standard version of C++.

C++03 (ISO/IEC 14882:2003): minor "bug-fix" to C++98 with no change to the language. Commonly refer to as C++98/C++03 or First C++ standard.

C++11 (ISO/IEC 14882:2011): Second standard version of C++. Informally called C++0x, as it was expected to finalize in 200x but was not released until 2011. It adds some new features to the language; more significantly, it greatly extends the C++ standard library and standard template library (STL).

C++14: Infomally called C++1y, is a small extension to C++11, with bug fixes and small improvement.

C++17: informally called C++1z.

C++2a: the next planned standard in 2020.

C++ Features

C++ is C. C++ supports (almost) all the features of C. Like C, C++ allows programmers to manage the memory directly, so as to develop efficient programs.

C++ is OO. C++ enhances the procedural-oriented C language with the object-oriented extension. The OO extension facilitates design, reuse and maintenance for complex software.

Template C++. C++ introduces generic programming, via the so-called template. You can apply the same algorithm to different data types.

STL. C++ provides a huge set of reusable standard libraries, in particular, the Standard Template Library (STL).

C++ Strength and Pitfall

C++ is a powerful language for high-performance applications, including writing operating systems and their subsystems, games and animation. C++ is also a complex and difficult programming language, which is really not meant for dummies. For example, to effectively use the C++ Standard Template Library (STL), you need to understand these difficult concepts: pointers, references, operator overloading and template, on top of the object-oriented programming concepts such as classes and objects, inheritance and polymorphism; and the traditional constructs such as decision and loop. C++ is performance centric. The C++ compiler does not issue warning/error message for many obvious programming mistakes, undefined and unspecified behaviors, such as array index out of range, using an uninitialized variable, etc, due to the focus on performance and efficiency rather than the ease of use - it assumes that those who choose to program in C++ are not dummies.

A secure website has https instead of http in web address true or false

Answers

Answer:

True

Explanation:

Beacuse security is s

The answer to the question is true

Ha Yoon sees funny quotes on top of images frequently in her social media feed. One day, she has an idea for one of her own. Which of these websites would be most likely to help her create what she wants? Group of answer choices a PDF generator an infographic template a meme generator a digital image editor

Answers

Answer:

Digital Image Editor

Explanation:

Ha Yoon is not trying to create a meme, or a text document (PDF), so the answer must be Digital Image Editor.

An array is another name for a list.

True or false. With explanation.

Answers

Answer:

True

Explanation:

An array could state a particular or indefinite number of items in order. The word is also synonymous to list

Answer:

True

Explanation:

mha ship what yo fave

Answers

Answer:

umm the first one I think..? lol

Answer:

both of them are my fav

Explanation:

Please Help. Which of the following statements about wide area networks are true? Select 3 options.


A. typically uses Eethernet and wireless routers to connect devices

B. connects devices in a large geographic area

C. is usually managed by a single business

D. may be controlled by multiple entities

E. connections usually occur through a public network

Answers

Answer:

B, D, E

Explanation:

The public Internet is largest WAN in the world.

A LAN (Local Area Network) typically uses Ethernet and Wireless Routers to connect devices.

A single business would not usually manage a WAN because this would create a monopoly, which is why competition is intentionally created between Internet Service Providers (ISPs), though sometimes a single business could manage a WAN via MPLS, etc.

Answer:

- connects devices in a large geographic area

- may be controlled by multiple entities

- connections usually occur through a public network

Explanation:

A wide area network (WAN) connects devices across a broader area like a city. It can provide connections across multiple countries. A wide area network may be managed and controlled by multiple entities. LANs connect to WANs to create a network of networks. The internet is considered the largest WAN.

(Confirmed on EDGE)

I hope this helped!

Good luck <3

Write a program that outputs a subtraction practice problem for a student, outputting the larger random number
first and the smaller random number second.

this is in C++ and i cant figure it out

Answers

Answer:

#include <stdio.h>

#include <stdlib.h>

#include <time.h>

int main(void)

{

   srand(time(NULL));

   int num1, num2;

   int val;

   while (true)

   {

       num1 = rand() % 100 + 1; //Random number between 1-100

       num2 = rand() % 100 + 1; //Random number between 1-100

       if (num1 >= num2)

       {

           printf("%d - %d = ", num1, num2);

           scanf("%d",&val);

           if (val == num1-num2)

           {

               printf("Correct!\n");

           }

           else

           {

               printf("Incorrect!\n");

           }    

       }

       else

       {

           printf("%d - %d = ", num2, num1);

           scanf("%d",&val);

           if (val == num2-num1)

           {

               printf("Correct!\n");

           }

           else

           {

               printf("Incorrect!\n");

           }

       }    

   }

}

Explanation:

First, we create two random numbers and save the values.  Then we check to see which value is larger.  Based on that, we change how we display the format to the user.  Then we check to see if the user input number is equivalent to the subtraction problem.  If it is, we display Correct!  Else, we display Incorrect!

Cheers.

Which team member on a project typically has a skill for creating visual interest?

Designer
Engineer
Programmer
Writer

Answers

Answer:

designer

Explanation:i took it and got it right

WILL GIVE BRAINLIEST!!!!!
This law of Sir Isaac Newton is what allows the spacecraft to lift off.

First Law

Second Law

Third Law

Answers

Third law :) Hope this helped you

Answer:

Third law

Explanation:

Third law allows the spacecraft to lift off.

Write a program to find the product of 3 numbers

Answers

Answer:

#include<iostream>

using namespace std;

int main()

{

   int a,b,c;

   cout<<"enter the value of a:";

   cin>>a;

   cout<<"enter the value of b:";

   cin>>b;

   cout<<"enter the value of c:";

   cin>>c;

   cout<<"product is:"<<(a*b*c);

   return 0;

}

Explanation:

The following codes have been written using Python.

x = int(input("Enter a number: "))

y = int(input("Enter a number: "))

z = int(input("Enter a number: "))

p = x*y*z

print(p, "is the product of", x, y, "and", str(z)+ ".")

Hope it helps. :)

what aspects of your life are most influenced by media and technology​

Answers

Answer:

Everyday life

Explanation:

Television

office work (computers )

Music

video games

ware house work uses technology

work from home jobs use technology

cellular towers

If a song is public domain, that means:

Check all that apply.

Portions of the song may be used at will.

The song may be recreated without fee.

No fee is owed for using the original song in its entirety.

None of the above.

Answers

Answer: C

Explanation:

Public Domain mean public owns it and it don’t belong to an individual author or artist. Anyone can use a public domain without obtaining permission but can’t ever own it

Answer:

It’s actually A,B, and C

Explanation:

I am timed and it needs to be in program C PLEASE help !!


Declare an array of doubles of size 170 called examBonus and initialize all the elements in the array to 5.5 (HINT: use a loop)

Answers

Answer:

Following are the declaration to this question:

double examBonus[] = new double[170]; // declaring the double array examBonus that holds 170 size value  

int x1;//defining an integer variable x1

for (x1=0;x1<170;x1++)//defining a for loop that initialize value in array

{

examBonus[x1] = 5.5;//assign value in array

}

Explanation:

In the above-given java program code, a double type array "examBonus" is declared, that holds a given size value, which is already defined in the question.

In the next step, an integer variable "x1" is defined which is used in the for loop that starts from 0 and ends when its value less than 170, and it assigns the value "5.5" in the above-given array.

Which of the following is a category of authentication tools. A something you have B something u see c something you hear d something you want

Answers

Answer:

Explanation:

Something you have.

Answer:

something you have

Explanation:

What can you do with python on a Chromebook

I am on a Chromebook and lately I have been leaning python on my PC at home, I had saw a video on how you could make python bots but that was on window OS and i am just asking if there is any thing cool i could be doing on my Chromebook and if possible only need a google chrome tab to work..

Answers

A Chromebook runs ChromeOS as its operating system and historically running anything other than a web app–such as Python–was challenging. However, that is no longer the case! You can now run Linux apps on ChromeOS which opens the door to using MiniConda to install Python 3.

C
Describe the scope of the variables in this code.
class cholesterol:
low Density = 0
highDensity = 0
class patient:
definit__(self, firstName.lastName,id Num):
self.firstName = f[rstName
self.lastName = lastName
self.id Num = idNum
def str (self):
return self.firstName +""+self.lastName + " + self.id Num
The scope of high Density is limited to the patient class
The scope of firstName is limited to the cholesterol class

Answers

Answer:

The scope of highDensity  is accessible by the entire program .

The scope of firstName  is limited to the patient class .

Explanation:

Correct answer edge 2020

The scope of highDensity is limited to the cholesterol class and the scope of the firstName is limited to the patient class.

Variable scope

The accessibility of a program is described by the scope of a variable.

To put it another way, it's the part of the program where the variable is identified.

The place you declared a variable determines the scope. There are two major scopes of variables in python.

Global variablesLocal variables

Therefore, the scope of highDensity is limited to the cholesterol class and the scope of the firstName is limited to the patient class.

learn more on variable scope here: https://brainly.com/question/21065208

#SPJ2

Which statement will remove 12:'uno' from the dictionary?

games = {8:'scrabble', 10:'xbox', 12:'uno'}

games.remove()

games.pop(12)

games.pop()

games.remove(12)

Answers

Answer: games.pop(12)

Explanation:

In a dictionary sequence, .pop() alone does not work as the variable needs to be defined. Adding 12 allows Python to identify this variable. .remove() does not work with or without a variable.

Answer:

games.pop(12)

Explanation:

Which are characteristics of interpreters? Select
all that apply.
translate high-level programming language
into binary computer machine language
offer a program run-time that is faster than
when a compiler is used for the translation
make it possible to change the source
program while the program is running
offer a program run-time that is slower than
when a compiler is used for the translation

Answers

Answer:

translation is used for interpretation

While Angela is making modifications to Katie’s Word document, she would like to inform Katie of the reasoning for the change.

Which feature should Angela use?

Track Changes
email
Comments
Save File

Answers

Answer:

i think it's comments

Not too sure

While Angela is making modifications to Katie’s Word document, the feature that Katie should use is comments. The correct option is c.

What is a Word document?

Microsoft Office is thought of as including Microsoft Word. Word, PowerPoint, Excel, Outlook, and a number of other programs are included in the Office suite of Microsoft tools.

These may be used on Windows or macOS and are suitable for both personal and professional use. They are not the same thing; Microsoft Word is merely one of such app.

A comment is a section or tool that can be used by the editor of the Word document. Comments can be added to correct the document and to give information that can be specified, and comments can be removed.

Therefore, the correct option is c. Comments.

To learn more about Word documents, refer to the below link:

https://brainly.com/question/26695071

#SPJ5

The image shows a sample group contract.

This group contract is important because it:

A) holds everyone accountable for their part in the project

B) summarizes expectations for the conduct of the group

C) discusses how adjustments to the schedule can be
made

D) assigns a time frame for each step to be completed

Answers

Answer: c

Explanation:I done this before;DDD

Answer:

Its A

Explanation:

Sorry the other guy is wrong

PLEASE HELP ASAP!!!!!!!!

Which option describes wearable technology? A. the incorporation of technology into objects we use regularly B. rugged technology that can withstand the elements without much damage C. computing systems that derive energy from the user's biological processes D. mobile technology that is extremely portable E. extremely small and powerful computing systems

Answers

Answer:

A

Explanation:

Things such as watches and clothes are common items which technology is incorporated to. This includes things implanted in the body. These are all wearble technologies.

Catherine purchased dried herbs from the grocery store. Which structure would she use if wanted to create a mixture of powdered herbs by pounding them repeatedly using a mortar and pestle?

A.

looping structure

B.

selection structure

C.

sequence structure

D.

conditional structure

Answers

Answer: C. sequence structure

Explanation:

Catherine would use the sequence structure to achieve her results of powdered herb after pounding the herbs.

In a sequence structure, an action, or event, tends to lead to the next action in an order which has been predetermined. The sequence can contain any number of actions, but no actions can or must be skipped in the sequence.

This means she has to go through the pounding process to achieve the powdered state.

Answer:

A. Looping structure

Explanation:

I just took the test

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